A motor driving circuit generates pulse driving signals, and controls the ON/OFF state of a switching circuit connected to a coil of a motor which is to be driven, thereby controlling the conduction period of the motor. A driving signal generating circuit generates the driving signals such that they are pulse modulated according to the torque target value for the motor, and outputs the driving signals to the switching circuit. A current detection circuit detects the current flowing through the coil of the motor. A current limiting circuit controls the logical values of the driving signals generated by the driving signal generating circuit such that the current detected by the current detection circuit does not exceed a predetermined current upper limit. The current limiting circuit increases the current upper limit according to the time elapsed in the starting operation of the motor. After the starting operation of the motor, the current upper limit is set to a predetermined fixed value.