An illuminated keyboard device includes plural keys, a membrane switch circuit module and plural light-emitting elements. The membrane switch circuit module is located under the plural keys. The plural light-emitting elements and plural light source wiring lines are disposed on the membrane switch circuit module. The plural light-emitting elements are connected with each other through the plural light source wiring lines. Since the plural light-emitting elements and the plural light source wiring lines are disposed on the membrane switch circuit module, it is not necessary to install a backlight module.