diff --git a/README.md b/README.md
index 7dccf18..9042d07 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ API client library for Kintone REST APIs on Java.
     Add dependency declaration in `build.gradle` of your project.
     ```
     dependencies {
-        implementation 'com.kintone:kintone-java-client:1.4.0'
+        implementation 'com.kintone:kintone-java-client:2.0.0'
     }
     ```
 - For projects using Maven  
@@ -17,7 +17,7 @@ API client library for Kintone REST APIs on Java.
     <dependency>
         <groupId>com.kintone</groupId>
         <artifactId>kintone-java-client</artifactId>
-        <version>1.4.0</version>
+        <version>2.0.0</version>
     </dependency>
   ```
 
diff --git a/build.gradle b/build.gradle
index 2dd226f..3e3e007 100644
--- a/build.gradle
+++ b/build.gradle
@@ -6,7 +6,7 @@ plugins {
     id 'com.github.hierynomus.license' version '0.16.1'
 }
 
-version = '1.4.1'
+version = '2.0.0'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
@@ -27,6 +27,7 @@ dependencies {
     implementation 'org.apache.httpcomponents.client5:httpclient5:5.3.1'
     implementation 'com.fasterxml.jackson.core:jackson-databind:2.16.1'
     implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.16.1'
+    implementation 'org.slf4j:slf4j-api:1.7.36'
 
     compileOnly 'org.projectlombok:lombok:1.18.30'
     annotationProcessor 'org.projectlombok:lombok:1.18.30'
diff --git a/docs/getting-started.md b/docs/getting-started.md
index 18ba1e2..06fa277 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -29,7 +29,7 @@ client.close();
 Add dependency declaration in `build.gradle` of your project.
 ```groovy
 dependencies {
-     implementation 'com.kintone:kintone-java-client:1.4.0'
+     implementation 'com.kintone:kintone-java-client:2.0.0'
 }
 ```
 
@@ -39,7 +39,7 @@ Add dependency declaration in `pom.xml` of your project.
 <dependency>
     <groupId>com.kintone</groupId>
     <artifactId>kintone-java-client</artifactId>
-    <version>1.4.0</version>
+    <version>2.0.0</version>
 </dependency>
 ```
 
@@ -152,6 +152,33 @@ Record newRecord = new Record().putField("text", new SingleLineTextFieldValue(va
 clientB.record().addRecord(app2, newRecord);
 ```
 
+#### Debug Logging
+
+Kintone Java Client outputs the contents of requests as debug logs through the logging interface
+provided by the [Simple Logging Facade for Java (SLF4J)](https://slf4j.org/) package.
+Therefore, you can check the logs by enabling the logger according to the configuration instructions
+of the logging implementation you are using. The logger name is `com.kintone.client.requestLog`.
+
+For example, if you are using [Logback](https://logback.qos.ch/) as your logging backend,
+the configuration file (`logback.xml`) would look like follows:
+
+```
+<configuration>
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <encoder>
+      <pattern>%d %logger %msg%n</pattern>
+    </encoder>
+  </appender>
+
+  <!-- Enable debug logs for Kintone Java Client -->
+  <logger name="com.kintone.client.requestLog" level="debug" />
+
+  <root level="info">
+    <appender-ref ref="STDOUT" />
+  </root>
+</configuration>
+```
+
 ### Record Operations
 
 `KintoneClient` supports record related operations through the `RecordClient` subcomponent.
diff --git a/src/main/java/com/kintone/client/InternalClientImpl.java b/src/main/java/com/kintone/client/InternalClientImpl.java
index def55c9..be0f7c9 100644
--- a/src/main/java/com/kintone/client/InternalClientImpl.java
+++ b/src/main/java/com/kintone/client/InternalClientImpl.java
@@ -14,6 +14,7 @@
 import com.kintone.client.model.BulkRequestContent;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -41,13 +42,21 @@
 import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuilder;
 import org.apache.hc.client5.http.protocol.HttpClientContext;
 import org.apache.hc.client5.http.ssl.SSLConnectionSocketFactoryBuilder;
-import org.apache.hc.core5.http.*;
+import org.apache.hc.core5.http.ClassicHttpResponse;
+import org.apache.hc.core5.http.ContentType;
+import org.apache.hc.core5.http.Header;
+import org.apache.hc.core5.http.HttpEntity;
+import org.apache.hc.core5.http.HttpHost;
+import org.apache.hc.core5.http.HttpStatus;
+import org.apache.hc.core5.http.ParseException;
 import org.apache.hc.core5.http.io.entity.ByteArrayEntity;
 import org.apache.hc.core5.http.io.entity.EntityUtils;
 import org.apache.hc.core5.http.protocol.HttpContext;
 import org.apache.hc.core5.http.ssl.TLS;
 import org.apache.hc.core5.pool.PoolConcurrencyPolicy;
 import org.apache.hc.core5.pool.PoolReusePolicy;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 class InternalClientImpl extends InternalClient {
 
@@ -61,6 +70,9 @@ class InternalClientImpl extends InternalClient {
     private final HttpHost proxyHost;
     private final BasicScheme proxyAuth;
 
+    private static final String REQUEST_LOGGER_NAME = "com.kintone.client.requestLog";
+    private final Logger logger = LoggerFactory.getLogger(REQUEST_LOGGER_NAME);
+
     InternalClientImpl(
             String baseUrl,
             Auth auth,
@@ -152,6 +164,20 @@ private HttpContext createHttpContext() {
         return context;
     }
 
+    private String readInputStream(InputStream in) {
+        try (InputStreamReader reader = new InputStreamReader(in, StandardCharsets.UTF_8)) {
+            StringBuilder sb = new StringBuilder();
+            char[] buffer = new char[1024];
+            int size;
+            while ((size = reader.read(buffer)) > 0) {
+                sb.append(buffer, 0, size);
+            }
+            return sb.toString();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     @Override
     <T extends KintoneResponseBody> T call(
             KintoneApi api, KintoneRequest body, List<ResponseHandler> handlers) {
@@ -168,6 +194,11 @@ <T extends KintoneResponseBody> T call(
             KintoneRequest body,
             Class<T> clazz,
             List<ResponseHandler> handlers) {
+        if (logger.isDebugEnabled()) {
+            String json = mapper.formatString(body);
+            logger.debug("request: {} {} {}", method, path, json);
+        }
+
         HttpUriRequest request = createJsonRequest(method, path, body);
         try {
             return httpClient.execute(
@@ -215,12 +246,19 @@ private List<KintoneResponseBody> parseBulkRequestResponse(
         return resultBodies;
     }
 
+    @SuppressWarnings("unchecked")
     @Override
     BulkRequestsResponseBody bulkRequest(BulkRequestsRequest body, List<ResponseHandler> handlers) {
+        KintoneHttpMethod method = KintoneApi.BULK_REQUESTS.getMethod();
         String path = getApiPath(KintoneApi.BULK_REQUESTS);
+        Map<String, Object> bulkRequestBody = createBulkRequestBody(body);
 
-        HttpUriRequest request =
-                createJsonRequest(KintoneApi.BULK_REQUESTS.getMethod(), path, createBulkRequestBody(body));
+        if (logger.isDebugEnabled()) {
+            String json = mapper.formatString(bulkRequestBody);
+            logger.debug("request: {} {} {}", method, path, json);
+        }
+
+        HttpUriRequest request = createJsonRequest(method, path, bulkRequestBody);
         try {
             return httpClient.execute(
                     request,
@@ -230,9 +268,17 @@ BulkRequestsResponseBody bulkRequest(BulkRequestsRequest body, List<ResponseHand
                                 parseResponse(
                                         response,
                                         stream -> {
-                                            @SuppressWarnings("unchecked")
-                                            Map<String, Object> responseMap = mapper.parse(stream, Map.class);
-                                            @SuppressWarnings("unchecked")
+                                            Map<String, Object> responseMap;
+                                            if (logger.isDebugEnabled()) {
+                                                String responseBody = readInputStream(stream);
+                                                logger.debug(
+                                                        "response status: {}, response body: {}",
+                                                        response.getCode(),
+                                                        responseBody);
+                                                responseMap = mapper.parseString(responseBody, Map.class);
+                                            } else {
+                                                responseMap = mapper.parse(stream, Map.class);
+                                            }
                                             List<Object> results = (List<Object>) responseMap.get("results");
                                             List<KintoneResponseBody> bodies =
                                                     parseBulkRequestResponse(body.getRequests(), results);
@@ -248,11 +294,19 @@ BulkRequestsResponseBody bulkRequest(BulkRequestsRequest body, List<ResponseHand
 
     @Override
     DownloadFileResponseBody download(DownloadFileRequest request, List<ResponseHandler> handlers) {
+        KintoneHttpMethod method = KintoneApi.DOWNLOAD_FILE.getMethod();
         String path = getApiPath(KintoneApi.DOWNLOAD_FILE);
-        HttpUriRequest req = createJsonRequest(KintoneApi.DOWNLOAD_FILE.getMethod(), path, request);
+
+        if (logger.isDebugEnabled()) {
+            String json = mapper.formatString(request);
+            logger.debug("request: {} {} {}", method, path, json);
+        }
+
+        HttpUriRequest req = createJsonRequest(method, path, request);
         KintoneResponse<DownloadFileResponseBody> r;
         try {
             ClassicHttpResponse response = httpClient.executeOpen(null, req, createHttpContext());
+            logger.debug("response status: {}", response.getCode());
             com.kintone.client.model.HttpResponse resp = new HttpResponseImpl(response);
             r = parseResponse(response, stream -> new DownloadFileResponseBody(resp));
         } catch (IOException e) {
@@ -281,9 +335,12 @@ KintoneResponse<UploadFileResponseBody> upload(
                 "file", new InputStreamBody(content, ContentType.create(contentType), filename));
 
         String headerContentType = "multipart/form-data; boundary=" + boundary;
+        KintoneHttpMethod method = KintoneApi.UPLOAD_FILE.getMethod();
         String path = getApiPath(KintoneApi.UPLOAD_FILE);
-        HttpUriRequest httpRequest =
-                createRequest(KintoneApi.UPLOAD_FILE.getMethod(), path, headerContentType, builder.build());
+
+        logger.debug("request: {} {}, file: {}", method, path, filename);
+
+        HttpUriRequest httpRequest = createRequest(method, path, headerContentType, builder.build());
         try {
             return httpClient.execute(
                     httpRequest,
@@ -314,6 +371,7 @@ private <T extends KintoneResponseBody> KintoneResponse<T> parseResponse(
                 result = converter.apply(response.getEntity().getContent());
             } else {
                 errorBody = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
+                logger.debug("response status: {}, response body: {}", statusCode, errorBody);
             }
         } catch (IOException | ParseException e) {
             throw new KintoneRuntimeException("Failed to request", e);
@@ -323,7 +381,17 @@ private <T extends KintoneResponseBody> KintoneResponse<T> parseResponse(
 
     private <T extends KintoneResponseBody> KintoneResponse<T> parseJsonResponse(
             ClassicHttpResponse response, Class<T> responseClass) {
-        return parseResponse(response, stream -> mapper.parse(stream, responseClass));
+        return parseResponse(
+                response,
+                stream -> {
+                    if (logger.isDebugEnabled()) {
+                        String body = readInputStream(stream);
+                        logger.debug("response status: {}, response body: {}", response.getCode(), body);
+                        return mapper.parseString(body, responseClass);
+                    } else {
+                        return mapper.parse(stream, responseClass);
+                    }
+                });
     }
 
     private void applyHandlers(KintoneResponse<?> response, List<ResponseHandler> handlers) {
diff --git a/src/main/java/com/kintone/client/JsonMapper.java b/src/main/java/com/kintone/client/JsonMapper.java
index dba4d88..d9f1c6f 100644
--- a/src/main/java/com/kintone/client/JsonMapper.java
+++ b/src/main/java/com/kintone/client/JsonMapper.java
@@ -51,6 +51,14 @@ byte[] format(Object obj) {
         }
     }
 
+    String formatString(Object obj) {
+        try {
+            return mapper.writeValueAsString(obj);
+        } catch (JsonProcessingException e) {
+            throw new KintoneRuntimeException("Failed to format request JSON", e);
+        }
+    }
+
     <T> T parse(InputStream stream, Class<T> clazz) {
         try {
             return mapper.readValue(stream, clazz);
@@ -59,6 +67,14 @@ <T> T parse(InputStream stream, Class<T> clazz) {
         }
     }
 
+    <T> T parseString(String input, Class<T> clazz) {
+        try {
+            return mapper.readValue(input, clazz);
+        } catch (IOException e) {
+            throw new KintoneRuntimeException("Failed to parse response JSON", e);
+        }
+    }
+
     <T> T convert(Object object, Class<T> clazz) {
         return mapper.convertValue(object, clazz);
     }