A motor driving apparatus drives an electric blower including a single-phase PM motor. The motor driving apparatus includes: a single-phase inverter that applies an alternating-current voltage to the single-phase PM motor; a rotor position detecting unit that outputs, to an inverter control unit, a position detecting signal corresponding to a rotational position of a rotor of the single-phase PM motor; a motor current detecting unit that outputs, to the inverter control unit, a signal corresponding to a motor current flowing to the single-phase PM motor; and the inverter control unit that outputs a driving signal to corresponding switching elements of the single-phase inverter on the basis of the position detecting signal and the motor current. The single-phase inverter performs control to increase or decrease effective electric power supplied to the single-phase PM motor. The air blower changes an air volume by the increase or decrease in effective electric power.