A motor vibration cause determination system includes: a vibration sensor unit capable of detecting vibration of the motor in a driving state, the vibration sensor unit detecting a first vibration which is vibration of the motor in a stand-alone state before shipping, a second vibration which is vibration of the motor in a stand-alone state and in a non-connection state in which the motor is not connected to the main shaft after shipping, and a third vibration which is vibration of the motor in the connection state; a vibration information storage unit that stores information on the vibration of the motor detected by the vibration sensor unit, the information including information on the first, second, and third vibrations; and a vibration cause determination unit that determines the cause of vibration occurring in the connection state on the basis of the vibration information stored in the vibration information storage unit.