PURPOSE: To provide a tester which can perform highly accurate noncontact inspection of the rotational performance and the causes of malfunction at the time of low flow rate from the outside of an indicating unit to be tested.

CONSTITUTION: When a main rotary disc 1 for rotating a motor 5 at a constant speed is rotated at a constant speed, a driven rotary disc 3 rotates with low torque and a drive magnet 4 fixed to the end of the shaft causes rotation of a magnet gear in an indicating unit to be tested. If the rotational performance of a gear mechanism in the indicating unit is abnormal, rotation of the driven rotary disc 3 varies and the rotational variation is detected by means of a photosensor 7. The detection data is then analyzed by means of a personal computer thus determining the rotational performance of the indicating unit, the cause of malfunction, etc.