A power accumulating unit of a power supply system includes a first switch section configured to achieve a first voltage output state in which an output voltage is substantially equal to a first motor driving voltage and a second switch section configured to achieve a second voltage output state in which the output voltage is substantially equal to a second motor driving voltage that is higher than the first motor driving voltage. A voltage switching control part is configured to perform a voltage switching control to switch between the first motor driving voltage and the second motor drivingvoltage by alternately operating the first and second switch sections to repeatedly switch between the first voltage output state and the second voltage output state.