An image forming apparatus includes a transfer unit transferring a toner image on a first face of a sheet, a fixing unit fixing the toner image onto the first face of the sheet, and a sheet detecting unit detecting the sheet in a sheet transporting path. The sheet detecting unit includes a rotator which rotates by a slide contact on a second face which is backside of the first face of the sheet, and a supporting member which supports the rotator rotatably. The rotator is comprised of a material which is charged by the slide contact on the sheet with a first polarity, the first polarity being opposed to a second polarity with which a toner of the toner image is charged. The supporting member is comprised of a material charged by the slide contact on the sheet with the second polarity.