To provide a motor abnormality detector which can detect the lock of a motor at a low cost, and provide a vehicle height adjuster.

This motor abnormality detector stops the current application to a motor 30, based on the voltage difference between the drive voltage supplied to the motor 30 and the control voltage of a controller 33 for controlling the drive of the motor 30, and this decides whether the motor 30 is locked, based on the regenerative voltage of the motor 30 of this time.