A motor rotation speed determining circuit is provided, and a processing of generating motor driving waveform is switched in accordance with the motor rotation speed. A resolver signal is converted to a digital value by an R/D converter, and inputted to a resolver value correction computing circuit via an R/D conversion interface. A current value of a motor M is converted to a digital value by an A/D converter. The resolver value correction computing circuit computes a resolver correction value of the inputted digital signal and calculates positional data from a corrected resolver value. The motor control computing circuit computes a current instruction value from a motor current value subjected to digital conversion by the A/D converter and a motor current instruction value etc., and a motor waveform output circuit generates a motor driving waveform from the current instruction value and outputs the same to a power module PM.