To provide a method and device which can surely detect the abnormality of the driving motor and mechanical driving system of a roller table, by diagnosing the operating states of the motor and system with accuracy at a low facility cost.

A device for diagnosing facility of roller table is provided with a current fluctuation detecting mechanism composed of a starting state detecting section 18 which detects the starting current and starting time of a motor 4 for driving a roll, immediately after the motor 4 is started by catching the current signal of the motor 4 one by one; and a roll eccentricity detecting section 20 which detects the current value of the motor 4 in a stable period and computes the oscillation period and amplitude of the current. The device continuously diagnoses a roller table in accordance with the operating state of the motor 4 from the current fluctuating behavior of the motor, in accordance with the operating state of the motor 4 during the period from the start to the stop of the motor 4, by successively switching the detecting sections to each other in accordance with the operating signal of the motor 4.