To provide a key top size inspection device that enables highly precise inspection.

A key top size inspection device includes a laser displacement gauge 18 that irradiates a keyboard 20 with a laser beam to measure the height of the keyboard 20 surface, an acquisition unit 37 that acquires the height according to the position of the laser displacement gauge 18 relative to the keyboard 20, and a calculation unit 38 for calculating the size of a key top 20b of the keyboard 20 on the basis of the acquired height.