A timepiece has a stepping motor for intermittently rotating hands to indicate the time, a solar cell for temporarily generating electric charge and capacitors for storing the generated electric charge to supply an operating voltage. A drive circuit repeatedly applies a combination of first and second consecutive driving pulses having electric powers proportional to the operating voltage to the stepping motor, while a detector detects the operating voltage. A control circuit is connected between the drive circuit and the detector for controlling the detector to effect the operating voltage detection after the application of the first driving pulse and before the application of the following second driving pulse. When decrease of the operating voltage is detected after the application of the first driving pulse, the operating voltage is increased before the application of the following second driving pulse so as to ensure the rotation of the hands.