diff --git a/build.gradle b/build.gradle
index 5e1ab97..903624f 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,6 +19,7 @@ dependencies {
     provided "org.embulk:embulk-core:0.7.0"
     // compile "YOUR_JAR_DEPENDENCY_GROUP:YOUR_JAR_DEPENDENCY_MODULE:YOUR_JAR_DEPENDENCY_VERSION"
     testCompile "junit:junit:4.+"
+    testCompile 'org.embulk:embulk-core:0.7.+:tests'
 }
 
 task classpath(type: Copy, dependsOn: ["jar"]) {
diff --git a/src/main/java/org/embulk/output/CommandFileOutputPlugin.java b/src/main/java/org/embulk/output/CommandFileOutputPlugin.java
index 5a2e76f..691a24b 100644
--- a/src/main/java/org/embulk/output/CommandFileOutputPlugin.java
+++ b/src/main/java/org/embulk/output/CommandFileOutputPlugin.java
@@ -5,6 +5,8 @@
 import java.io.OutputStream;
 import java.io.FilterOutputStream;
 import java.io.IOException;
+
+import com.google.common.annotations.VisibleForTesting;
 import org.slf4j.Logger;
 import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableList;
@@ -32,11 +34,6 @@ public interface PluginTask
         public String getCommand();
     }
 
-    public static final List<String> SHELL = ImmutableList.of(
-        // TODO use ["PowerShell.exe", "-Command"] on windows?
-        "sh", "-c"
-    );
-
     @Override
     public ConfigDiff transaction(ConfigSource config, int taskCount,
             FileOutputPlugin.Control control)
@@ -68,8 +65,9 @@ public TransactionalFileOutput open(TaskSource taskSource, final int taskIndex)
     {
         PluginTask task = taskSource.loadTask(PluginTask.class);
 
+        List<String> shell = new ShellFactory().build().get();
         List<String> cmdline = new ArrayList<String>();
-        cmdline.addAll(SHELL);
+        cmdline.addAll(shell);
         cmdline.add(task.getCommand());
 
         logger.info("Using command {}", cmdline);
@@ -77,6 +75,26 @@ public TransactionalFileOutput open(TaskSource taskSource, final int taskIndex)
         return new PluginFileOutput(cmdline, taskIndex);
     }
 
+    @VisibleForTesting
+    static class ShellFactory
+    {
+        private List<String> shell;
+
+        public List<String> get() {
+            return this.shell;
+        }
+
+        public ShellFactory build() {
+            String osName = System.getProperty("os.name");
+            if(osName.indexOf("Windows") >= 0) {
+                this.shell = ImmutableList.of("PowerShell.exe", "-Command");
+            } else {
+                this.shell = ImmutableList.of("sh", "-c");
+            }
+            return this;
+        }
+    }
+
     private static class ProcessWaitOutputStream
             extends FilterOutputStream
     {
diff --git a/src/test/java/org/embulk/output/TestCommandFileOutputPlugin.java b/src/test/java/org/embulk/output/TestCommandFileOutputPlugin.java
index 22d1032..52ff848 100644
--- a/src/test/java/org/embulk/output/TestCommandFileOutputPlugin.java
+++ b/src/test/java/org/embulk/output/TestCommandFileOutputPlugin.java
@@ -1,5 +1,39 @@
 package org.embulk.output;
 
+import com.google.common.collect.ImmutableList;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.embulk.EmbulkTestRuntime;
+import org.embulk.output.CommandFileOutputPlugin.ShellFactory;
+
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
 public class TestCommandFileOutputPlugin
 {
+    @Rule
+    public EmbulkTestRuntime runtime = new EmbulkTestRuntime();
+
+    private ShellFactory shellFactory;
+
+    @Before
+    public void createResources()
+    {
+        shellFactory = new ShellFactory().build();
+    }
+
+    @Test
+    public void testShell() {
+        List<String> shell = shellFactory.get();
+        String osName = System.getProperty("os.name");
+        List<String> actualShellCmd;
+        if (osName.indexOf("Windows") >= 0) {
+            actualShellCmd = ImmutableList.of("PowerShell.exe", "-Command");
+        } else {
+            actualShellCmd = ImmutableList.of("sh", "-c");
+        }
+        assertEquals(actualShellCmd, shell);
+    }
 }