diff --git a/src/main/java/info/istlab/Zemi01/TextEditor.java b/src/main/java/info/istlab/Zemi01/TextEditor.java
index e0a7d8a..8659215 100644
--- a/src/main/java/info/istlab/Zemi01/TextEditor.java
+++ b/src/main/java/info/istlab/Zemi01/TextEditor.java
@@ -52,7 +52,7 @@
         JButton speakButton = new JButton("読み上げ開始");
         speakButton.addActionListener(e -> {
             String txt = textArea.getSelectedText();
-            if (txt.length() == 0) {
+            if (txt == null || txt.length() == 0) {
                 txt = textArea.getText();
             }
             say = new Say(txt);