PURPOSE: To equalize the starting voltage for an accelerator driving motor of an accelerator into which a torsion spring is integrated, in normal rotation and in the reverse rotation by connecting a characteristic adjusting circuit in which a diode and a resistance are connected together in parallel, with a feeder circuit of the accelerator driving motor in such a way that the driving current runs forward in the diode in the normal rotation of an intermediary installation motor as well as running through the resistance at the time of reverse rotation.

CONSTITUTION: When a motor M is driven in normal rotation, the current from a control unit 2 runs starting with a feeder circuit 3b, to a diode 41, the motor M, a limit switch 12, a diode 21 of a characteristic adjusting circuit 20, and to the control unit 2. Since the current runs forward to the diode 21, the starting voltage of the motor M alone is generated at the control unit. When the motor M is driven in reverse rotation, the current from the unit 2 runs starting with the feeder circuit 3a, through the resistance 22 of the characteristic adjusting circuit 20, a diode 42, the motor M, and to a limit switch 11. Since the current runs in the resistance 22 of the characteristic adjusting circuit 20, the sum of the voltage drop of the resistance 22 and the starting voltage of the motor M is generated at the unit 2. The voltage in reverse rotation is thus almost at the same level with that in normal direction.