An image forming apparatus includes an image forming portion, a fixing unit, a position adjustment mechanism, a number-of-printed-sheets counter, and a control unit. The image forming portion includes an image carrier, a charging unit, an exposure unit, a developing unit, and a transfer member. The fixing unit has a heated rotary member and a pressing member and heats and presses the sheet passing through a fixing nip portion. A position adjustment mechanism adjusts the width-direction position of the sheet parallel to the scanning direction of optical scanning by the exposure unit. Every time the number of printed sheets reaches a predetermined number, the control unit makes the correction unit shift the width-direction position of the sheet by a predetermined amount and changes the start position of scanning by the exposure unit on the image carrier according to the direction and amount of shift.