A shaft accuracy measuring device includes: a measurement unit including a light projecting unit that projects a measuring light and a light receiving unit that receives the measurement light projected by the light projecting unit; a motor installation unit that installs the motor such that the output shaft of the motor is disposed between the light projecting unit and the light receiving unit; and a calculation unit that calculates at least one of axial run-out, center run-out, and face run-out of the motor based on a measurement result of the measurement unit.