Thank you for your advice.
I have changed the file name like below.
But my translation is not reflected.
Why???
wp-content/languages/themes/ami3-ja_JA.mo
wp-content/languages/themes/ami3-ja_JA.po
wp-content/languages/plugins/ads-ja_JA.mo
wp-content/languages/plugins/ads-ja_JA.po
My translation to Japanese language is not reflect.
I have put the po and mo files to the place shown below.
wp-content/languages/themes/davinci-ja.mo
wp-content/languages/themes/davinci-ja.po
wp-content/languages/plugins/alids-ja.mo
wp-content/languages/plugins/alids-ja.po
Is the place correct?