diff --git a/src/main/java/org/fluentd/logger/sender/RawSocketSender.java b/src/main/java/org/fluentd/logger/sender/RawSocketSender.java
index 5b440dc..bddd9f8 100644
--- a/src/main/java/org/fluentd/logger/sender/RawSocketSender.java
+++ b/src/main/java/org/fluentd/logger/sender/RawSocketSender.java
@@ -82,10 +82,10 @@ private void connect() throws IOException {
         }
     }
 
-    private void reconnect(boolean forceReconnection) throws IOException {
+    private void reconnect() throws IOException {
         if (socket == null) {
             connect();
-        } else if (forceReconnection || socket.isClosed() || (!socket.isConnected())) {
+        } else if (socket.isClosed() || (!socket.isConnected())) {
             close();
             connect();
         }
@@ -178,7 +178,7 @@ private synchronized boolean send(byte[] bytes) {
     public synchronized void flush() {
         try {
             // check whether connection is established or not
-            reconnect(!reconnector.isErrorHistoryEmpty());
+            reconnect();
             // write data
             out.write(getBuffer());
             out.flush();
@@ -187,6 +187,7 @@ public synchronized void flush() {
         } catch (IOException e) {
             LOG.error(this.getClass().getName(), "flush", e);
             reconnector.addErrorHistory(System.currentTimeMillis());
+            close();
         }
     }
 
diff --git a/src/test/java/org/fluentd/logger/TestFluentLogger.java b/src/test/java/org/fluentd/logger/TestFluentLogger.java
index 3a9d7b2..abfe7d1 100644
--- a/src/test/java/org/fluentd/logger/TestFluentLogger.java
+++ b/src/test/java/org/fluentd/logger/TestFluentLogger.java
@@ -3,7 +3,6 @@
 import org.fluentd.logger.sender.Event;
 import org.fluentd.logger.sender.NullSender;
 import org.fluentd.logger.util.MockFluentd;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.msgpack.MessagePack;
 import org.msgpack.unpacker.Unpacker;
@@ -20,6 +19,8 @@
 import java.util.concurrent.TimeUnit;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class TestFluentLogger {
     private Logger _logger = LoggerFactory.getLogger(TestFluentLogger.class);
@@ -227,12 +228,14 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
 
         // start loggers
         FluentLogger logger = FluentLogger.getLogger("testtag", host, port);
+        assertFalse(logger.isConnected());
         {
             Map<String, Object> data = new HashMap<String, Object>();
             data.put("k1", "v1");
             data.put("k2", "v2");
             logger.log("test01", data);
         }
+        assertTrue(logger.isConnected());
 
         TimeUnit.MILLISECONDS.sleep(500);
         _logger.info("Closing the current fluentd instance");
@@ -240,13 +243,14 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         fluentd1.close();
 
         TimeUnit.MILLISECONDS.sleep(500);
-
+        assertTrue(logger.isConnected());
         {
             Map<String, Object> data = new HashMap<String, Object>();
             data.put("k3", "v3");
             data.put("k4", "v4");
             logger.log("test01", data);
         }
+        assertFalse(logger.isConnected());
 
         final List<Event> elist2 = new ArrayList<Event>();
         MockFluentd fluentd2 = new MockFluentd(port, new MockFluentd.MockProcess() {
@@ -274,6 +278,7 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
             data.put("k6", "v6");
             logger.log("test01", data);
         }
+        assertTrue(logger.isConnected());
 
         // close loggers
         FluentLogger.closeAll();
@@ -281,12 +286,10 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
 
         fluentd2.close();
 
-
         // wait for unpacking event data on fluentd
         TimeUnit.MILLISECONDS.sleep(2000);
         threadManager.join();
 
-
         // check data
         assertEquals(1, elist1.size());
         assertEquals("testtag.test01", elist1.get(0).tag);
@@ -361,6 +364,14 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
 
         final FluentLogger logger = FluentLogger.getLogger(null, host, port);
         ExecutorService executorService = Executors.newFixedThreadPool(N);
+        /*
+         * Each thread emits the following events LOOP times
+         * Thread#0: {'0' => 0}
+         * Thread#1: {'0' => 0, '1' => 1}
+         * Thread#2: {'0' => 0, '1' => 1, '2' => 2}
+         *    :
+         * Thread#(N-1): {'0' => 0, '1' => 1, '2' => 2 ... '(N-1)' => (N-1)}
+         */
         for (int i = 0; i < N; i++) {
             final int ii = i;
             executorService.execute(new Runnable() {
diff --git a/src/test/java/org/fluentd/logger/sender/TestRawSocketSender.java b/src/test/java/org/fluentd/logger/sender/TestRawSocketSender.java
index ef234a5..11e9592 100644
--- a/src/test/java/org/fluentd/logger/sender/TestRawSocketSender.java
+++ b/src/test/java/org/fluentd/logger/sender/TestRawSocketSender.java
@@ -24,6 +24,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 
@@ -275,9 +276,11 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         fluentd.start();
 
         Sender sender = new RawSocketSender("localhost", port);
+        assertFalse(sender.isConnected());
         Map<String, Object> data = new HashMap<String, Object>();
         data.put("key0", "v0");
         sender.emit("tag0", data);
+        assertTrue(sender.isConnected());
 
         // close fluentd to make the next sending failed
         TimeUnit.MILLISECONDS.sleep(500);
@@ -289,6 +292,7 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         data = new HashMap<String, Object>();
         data.put("key0", "v1");
         sender.emit("tag0", data);
+        assertFalse(sender.isConnected());
 
         // wait to avoid the suppression of reconnection
         TimeUnit.MILLISECONDS.sleep(500);