An image forming apparatus includes a driving unit including a driving source, a drive gear, a first support member that holds the driving source and includes a first support portion that supports one end portion of a rotation shaft of the drive gear, and a second support member that includes a second support portion that supports another end portion of the rotating shaft. The first support member includes a fastening hole disposed in a projection plane obtained by projecting the second support portion in the rotation axis direction of the drive gear. The second support member is disposed upstream of the first support member in a fastening direction, and includes a mounting portion extending so as to be in contact with the first support portion in the projection plane, the mounting portion including an attachment hole, the attachment hole being disposed at a position overlapping the fastening hole.