An object of the present invention is based on the detection signal in the transmission to provide a continuously variable transmission that can be determined over the region itself occurs. Accordingly, the present invention, the drive shaft and a driven shaft and, with the drive shaft and each provided a drive pulley to a driven shaft and the driven pulley, and a V belt wound on the drive pulley and the driven pulley for transmitting a rotational force of the driving shaft to the driven shaft, the drive to be included in any of the pulley and the driven pulley and the V belt is wound transmission provided with a movable pulley disk capable of controlling the number of revolutions outputted from a driven shaft continuously adjustable traveling along the pulley axis direction so that the adjustable pulley width characterized in that the displacement control motor for generating a rotation in order to control the amount of movement of the movable pulley disk, and the motion conversion member receives a rotational force of the displacement adjustment motor that moves with the movable pulley disk, while moving in the axial direction, the drive shaft and a drive shaft revolution sensor for detecting the number of revolutions of, the number and the driven shaft rotational speed sensor for detecting the number of revolutions of the driven shaft, and a displacement sensor arranged to detect the amount of movement of the motion converting member, rotating the drive shaft by in accordance with the number of revolutions of the drive shaft detected by the sensor controls the rotation of the displacement control motor comprising a controller for the said driven shaft controlled to output a constant number of revolutions, measurement of the controller can rotate the driven shaft sensor and the displacement sensor based on the value and the number of revolutions of the motor characterized in that the displacement control part that determines a fault occurs.