A reference vibrator 10 of the present invention includes: a vibrator body 11 configured to mount to a mount 4 in an unbalance measurement device 1 to which a rotary product is mounted at the time of unbalance measurement, in a same mounting state as the rotary product; a vibration generator 12 fixed to the vibrator body 11 and that applies vibrations to the vibrator body 11; and a control unit 13 that controls the vibration generator 12. Because vibration is caused by the vibration generator 12 fixed to the vibrator body 11, repeatability of vibration force is high. This makes it possible to apply vibrations for repeatability check to the unbalance measurement device 1 with an accurate vibration force. Thus, variations in vibration force can be eliminated, and the repeatability of the unbalance measurement device 1 can be properly checked.