A motor driving circuit comprising a pulse generating circuit for generating plural types of pulse trains, a modulation pulse generating circuit connected to the pulse generating circuit, a semiconductor driving circuit connected to an output of the modulation pulse generating circuit for providing operating power to a motor winding, a detecting circuit connected to the driving circuit for detecting a voltage induced in the motor winding, and a counting circuit connected to the detecting circuit. The detecting circuit has means for setting reference levels, detects the voltage induced in the motor winding in accordance with the reference levels during the time the semiconductor driving circuit is non-conducting, and sends control signals for regulating a next produced modulation pulse width to the counting circuit, and the modulation pulse generating circuit shapes the modulation pulse from the plural types of pulse trains of the pulse generating circuit in accordance with outputs of the counting circuit so as to drive the motor uniformly.