To solve the problem that a reference position sensor is required for detecting the reference position of a stepping motor.

In the stepping motor driving device having a control means 6 for controlling power supply to the stepping motor and controlling the rotational position of the stepping motor within a rotation allowable range mechanically limited by stoppers 4, 5 on the basis of the power supply control, the control means 6 sets the same power supply state as the power supply state for stopping the motor at a reference step position G optionally set within the rotation allowable range as initializing power supply control for rotating the motor to the reference step position G (I), and then executes the change control of the same power supply state as the power supply state for reciprocally rotating the motor between both the ends of the rotation allowable range with the reference step position G as a star point and an end point (II).