An image forming apparatus includes: an image generating engine for forming a toner image and transferring the toner image onto a recording material in a transfer region; an upper supply tray disposed above the image generating engine and accommodating the recording material; and a fixing unit for thermally fixing the toner image transferred on the recording material in the transfer region of the image generating engine. The fixing unit is disposed between the image generating engine and the upper supply tray and includes a thermal fusing unit positioned at a location closer to a center of a case body of the image forming apparatus than sidewalls of the case body.