An image forming apparatus comprising: first and second switching means (801, 802) configured to be disposed in respective ones of two supply paths that are different in polarity and over which alternating-current power from a commercial alternating-current power supply is supplied, and switch supply and shut off of the alternating-current power; a power supplied device configured to be disposed downstream of said first and second switching means (801, 802) and be supplied with the alternating-current power; and a control means configured to, when supply of the alternating-current power from the commercial alternating-current power supply to said power supplied device is started, control said first and second switching means (801, 802) to switch one of said first and second switching means (801, 802) into supply state and then switch the other one of said first and second switching means (801, 802) into supply state; characterized in a noise filter circuit configured to be disposed downstream of said first and second switching means (801, 802) and filter out noise on the two supply paths; wherein said power supplied device is configured to be disposed downstream of said noise filter circuit and be supplied with the alternating-current power through said noise filter circuit; and said control means is configured to, when supply of the alternating-current power from the commercial alternating-current power supply to said power supplied device is started, control said first and second switching means (801, 802) to switch one of said first and second switching means (801, 802) into supply state and then switch the other one of said first and second switching means (801, 802) into supply state so that the number of times said first switching means (801, 802) is switched into supply state first and the number of times said second switching means (801, 802) is switched into supply state first can be substantially equal per predetermined number of times the alternating-current power is supplied to said power supplied device. first and second switching means (801, 802) configured to be disposed in respective ones of two supply paths that are different in polarity and over which alternating-current power from a commercial alternating-current power supply is supplied, and switch supply and shut off of the alternating-current power; a power supplied device configured to be disposed downstream of said first and second switching means (801, 802) and be supplied with the alternating-current power; and a control means configured to, when supply of the alternating-current power from the commercial alternating-current power supply to said power supplied device is started, control said first and second switching means (801, 802) to switch one of said first and second switching means (801, 802) into supply state and then switch the other one of said first and second switching means (801, 802) into supply state; characterized in a noise filter circuit configured to be disposed downstream of said first and second switching means (801, 802) and filter out noise on the two supply paths; wherein said power supplied device is configured to be disposed downstream of said noise filter circuit and be supplied with the alternating-current power through said noise filter circuit; and said control means is configured to, when supply of the alternating-current power from the commercial alternating-current power supply to said power supplied device is started, control said first and second switching means (801, 802) to switch one of said first and second switching means (801, 802) into supply state and then switch the other one of said first and second switching means (801, 802) into supply state so that the number of times said first switching means (801, 802) is switched into supply state first and the number of times said second switching means (801, 802) is switched into supply state first can be substantially equal per predetermined number of times the alternating-current power is supplied to said power supplied device.