An image forming apparatus includes an image forming unit configured to form an image on a recording medium, a first frame and a second frame configured to support the image forming unit, the first frame and the second frame being provided to sandwich the image forming unit, an outer casing member extending along a surface of the first frame configured to cover the first frame, and an electronic circuit substrate that is provided on a side opposite to the image forming unit via the surface of the first frame, and is provided between the first frame and the outer casing member, wherein the electronic circuit substrate extends in a direction crossing a surface of the outer casing member.