An image forming apparatus includes a main body including a first guide portion and a second guide portion, a process cartridge including a photosensitive drum, a support frame configured to support the process cartridge and move between an inside position and an outside position. The support frame includes a first side frame. The first side frame includes a first guided portion to be guided by the first guide portion. The second side frame includes a second guided portion guided by the second guide portion A dimension of the first side frame is greater than or equal to a dimension of the first side frame. A dimension of the second side frame is greater than or equal to a dimension of the second side frame.