Abstract: A keyboard device includes a sensor (1) for detecting whether hands of a user are present at the home position, a function switching key to select one of the two functions by pressing a key (2), a sensor validating/invalidating switch (3) to changeover the validation/invalidation of the detection result of the sensor, and a microcomputer 6 for selecting the function according to the detection result of the sensor (1) when the sensor validating/invalidating switch (3) is validated, and by the function switching key when the same is invalidated.