An object is to realize acoustic noise reduction under a wide range of rotating speeds and together with PWM control. A signal (VCTL1) is generated as a trapezoidal wave repeatedly rising and falling in each given electrical angle section extending before and after the current-supply pattern is switched in accordance with the electrical angle of a rotor of a motor, and a signal (VCTL2) is generated in the opposite phase. A control circuit (22) appropriately selects among the signals (VCTL1 and VCTL2) and a given signal (SCTL) and inputs them to comparators (59 to 61). The comparators (59 to 61) compare the input signals with a carrier signal (B6) provided as a triangular wave. Switch elements for controlling the current-supply pattern to the motor turn on/off on the basis of output signals (C1 to C6) from the comparators (59 to 61). As a result, the current-supply pattern is switched softly by PWM control in the electrical angle section mentioned above.