An image forming apparatus comprising: a first light source configured to emit a first light beam for exposing a first photoconductor; a second light source configured to emit a second light beam for exposing a second photoconductor; a rotating polygon mirror configured to deflect the first light beam and the second light beam so that the first light beam scans the first photoconductor and the second light beam scans the second photoconductor, the rotating polygon mirror deflecting the first light beam and the second light beam toward opposite sides with the rotating polygon mirror being interposed therebetween; an optical box where the first light source, the second light source, and the rotating polygon mirror are disposed; a cover configured to cover the optical box, the cover including a first transparent window and a second transparent window disposed on opposite sides with the rotating polygon mirror being interposed therebetween, the first transparent window passing therethrough the first light beam deflected by the rotating polygon mirror, the second transparent window passing therethrough the second light beam deflected by the rotating polygon mirror; a shutter that is disposed so as to oppose the cover, the shutter sliding so as to reciprocate between a position where the first transparent window and the second transparent window are covered and a position that is displaced from a light path of the first light beam that has passed through the first transparent window and from a light path of the second light beam that has passed through the second transparent window; and a shutter moving mechanism (807, 310) including pushing means and a spring, the pushing means sliding the shutter by pushing the shutter, the spring being connected to the shutter and the cover, being deformed so that an elastic force that urges the shutter in a direction opposite to a pushing direction of the pushing means increases as an amount of movement of the shutter pushed by the pushing means increases, and sliding the shutter in the opposite direction by the elastic force, characterized by a recess provided at an opposing surface of the cover opposing the shutter and at a side opposite to the first light source and the second light source with the rotating polygon mirror being interposed therebetween, the recess being recessed towards an inner side of the optical box, covered by the cover, at a location between the first transparent window and the second transparent window, and wherein a connection portion with which the spring connected to the shutter is connected is provided at the recess. a first light source configured to emit a first light beam for exposing a first photoconductor; a second light source configured to emit a second light beam for exposing a second photoconductor; a rotating polygon mirror configured to deflect the first light beam and the second light beam so that the first light beam scans the first photoconductor and the second light beam scans the second photoconductor, the rotating polygon mirror deflecting the first light beam and the second light beam toward opposite sides with the rotating polygon mirror being interposed therebetween; an optical box where the first light source, the second light source, and the rotating polygon mirror are disposed; a cover configured to cover the optical box, the cover including a first transparent window and a second transparent window disposed on opposite sides with the rotating polygon mirror being interposed therebetween, the first transparent window passing therethrough the first light beam deflected by the rotating polygon mirror, the second transparent window passing therethrough the second light beam deflected by the rotating polygon mirror; a shutter that is disposed so as to oppose the cover, the shutter sliding so as to reciprocate between a position where the first transparent window and the second transparent window are covered and a position that is displaced from a light path of the first light beam that has passed through the first transparent window and from a light path of the second light beam that has passed through the second transparent window; and a shutter moving mechanism (807, 310) including pushing means and a spring, the pushing means sliding the shutter by pushing the shutter, the spring being connected to the shutter and the cover, being deformed so that an elastic force that urges the shutter in a direction opposite to a pushing direction of the pushing means increases as an amount of movement of the shutter pushed by the pushing means increases, and sliding the shutter in the opposite direction by the elastic force, characterized by a recess provided at an opposing surface of the cover opposing the shutter and at a side opposite to the first light source and the second light source with the rotating polygon mirror being interposed therebetween, the recess being recessed towards an inner side of the optical box, covered by the cover, at a location between the first transparent window and the second transparent window, and wherein a connection portion with which the spring connected to the shutter is connected is provided at the recess.