PURPOSE: To perform en efficient drive by driving a pulse motor with a small current at the time of low-speed rotation and which a large current at the time of high-speed operation through making the output of a reference current value generator to be inputted to a comparator lower at the time of the low-speed rotation and higher at the time of the high-speed rotation according to the number of revolutions of the motor in the constant-current drive system of the pulse motor.

CONSTITUTION: An apparatus is constituted by a current sensor 1 for converting a current flowing through a motor 6 into a voltage and outputting the voltage, a reference current value generator 2 for converting a reference current, which is set low at the time of low-speed rotation and high at the time of high-speed rotation according to the number of revolutions of the motor, into a voltage and outputting the voltage; a comparator 3 for comparing the output of the current sensor 1 and that of the reference current value generator 2, a controller 4 for outputting a drive pulse to be turned ON and OFF according to the output signal of the comparator 3, and a driver 5 for driving the motor 6 by the drive pulse outputted from the controller 4. Thus, an appropriate torque corresponding to the number of revolutions can be obtained and the motor can be driven to rotation efficiently.