To provide a voltage supply device which acts in either a first power mode in which voltage is supplied to both first load and second load or a second power mode in which voltage is supplied to the first load, but is not supplied to the second load, and which is surely made to act in the second mode in a period during which the voltage is preset to be supplied in the second power mode.

An image forming apparatus 220 controls a power supply ON/OFF part 41 to act in a deep sleep mode when a switch-off state is changed over to a switch-on state by a main switch 410 and the present time is included in a forced deep sleep mode period.