A keyboard device for an electronic keyboard instrument, ensuring stable pivotal motion of each key and improved in each of assembly and disassembly. Each key extends in a front-rear direction and has a pivot shaft extending at a rear end in a left-right direction. A keyboard chassis has a mounting portion and key-separating support portions each for supporting the pivot shaft. A pivot shaft bearing member has a pivot shaft support portion cooperating with each key-separating support portion to form a bearing for the pivot shaft, supporting each key pivotally movable, and is removably mounted to the mounting portion. During assembly, with each key engaged with the key-separating support portion via the pivot shaft and held on the keyboard chassis, the mounting portion remains exposed, enabling the bearing member to be mounted from above or rear.