An electronic keyboard instrument capable of suppressing warpage of a keybed having a keyboard placed thereon and improving the appearance of the instrument by shared use of a backboard covering an instrument body and a speaker box. A piano body of an electronic piano has a keybed. A bottom board is disposed below the keybed in a manner spaced therefrom and extends further rearward than a rear end thereof. A front board is erected on a front end of the bottom board and connected to the keybed. The speaker box accommodates a speaker. A screen board is erected rearward of the front board in the speaker box on the bottom board, and connected to the keybed. A backboard is connected to the rear end of the bottom board in a manner covering the rear sides of the piano body and the speaker box.