A keyboard device capable of securing a wider rotation region of a hammer is provided. The keyboard device includes: a key; a connection portion connected between the key and a frame, the connection portion including: a first region extending in a key-longitude direction and having a depressed portion caved upward; and a second region arranged so as to line up with the first region in the key-longitude direction, located in at least a part of a region other than the depressed portion, having flexibility in a yawing direction; and a hammer mechanism operated according to a strike of the key. A part of the hammer mechanism is positioned in the depressed portion in a state where the key is struck.