diff --git a/ch02/ppmi.py b/ch02/ppmi.py
index 008d75ed..54b4f04d 100644
--- a/ch02/ppmi.py
+++ b/ch02/ppmi.py
@@ -12,7 +12,7 @@
 W = ppmi(C)
 
 np.set_printoptions(precision=3)  # 有効桁３桁で表示
-print('covariance matrix')
+print('co-occurrence matrix')
 print(C)
 print('-'*50)
 print('PPMI')