Image forming apparatus 10 of the present invention is an apparatus for forming an image on a surface of recording medium P by applying laser light to recording medium P, the apparatus including a plurality of light sources 31 each of which emits laser light, a plurality of optical fibers 23 and 42 through which laser light respectively emitted from light sources 31 propagates, holder 43 that holds optical fibers 42, and fly-eye lens 50, cylindrical lens array 60, aperture array 70, lens 80a and lens 80b through which laser light emitted from end surfaces of optical fibers 42 passes, wherein each of apertures 71 of aperture array 70 is rectangular.