An image forming apparatus, including a photosensitive drum, an exposure head, a base frame, and a spring, is provided. The exposure head includes light emitters, a lens array, and a head frame, and is movable between an exposable position and a retracted position. The base frame supports the photosensitive drum and includes a reference face. The reference face is configured to define a position of the exposure head with regard to a sub-scanning direction, which is orthogonal to a direction of an optical axis of the light from the light emitters and to a direction of a rotation axis of the photosensitive drum, by being contacted by the head frame of the exposure head when the exposure head is at the exposable position. The spring is arranged in the head frame and presses the head frame toward the reference face.