An image forming apparatus includes a main assembly; a transfer portion; a fixing portion; an opening provided on the main assembly; a door; a first guiding member provided in the main assembly and a second guiding member provided on the door and is interlaced with the first guiding member; a supporting plate supporting the first guiding member; the first guiding member has a convex curved surface of a shape such that a force received by the first guiding member when the door is opened with a sheet jammed between the first and second guiding members is in a direction of urging the first guiding member to the supporting plate.