A microprocessor of the motor control apparatus acquires a zero-cross detection signal from a zero-cross detection section and a load current from a current detection section at a prescribed sampling period. The processor obtains a load current instant value every sampling period and a corresponding sine-functional value from a sine-functional value table to calculate a compensation value for the load current instant value. The processor also calculates a load current compensation total value by adding the compensation value by the predetermined number of times of sampling and compares the load current compensation total value with a load current reference value to obtain a difference therebetween. In response to the difference, an instruction value for delay time that determines the output timing of a trigger signal to a switching element is changed so that power consumption of the motor falls within a prescribed range.