An image forming apparatus includes: a recording medium cassette storing recording medium; an image forming unit, a feed unit; an upper frame that supports the image forming unit and the feed unit; and a lower frame in which the recording medium cassette is detachably attached, the upper frame being disposed on the lower frame, and the lower frame having rigidity lower than the rigidity of the upper frame, the lower frame including a rail for guiding the recording medium cassette to a predetermined receiving position, wherein the feed unit has a groove portion formed along a direction parallel to a horizontal direction, the recording medium cassette has a first convex portion which is fitted in the groove portion when the recording medium cassette is attached in the lower frame, the recording medium cassette having a second convex portion which is contact with a portion of the rail of the lower frame.