An image forming apparatus includes: a light-emitting element that includes light-emitting point groups; and an optical system that includes imaging systems focusing light from light-emitting points of the light-emitting point groups, wherein the light-emitting point groups and the imaging systems are combined into sets, the light-receiving surface has a cylindrical shape, each imaging system has a negative imaging magnification, light-emitting point groups are arranged at different positions, the imaging systems adjacent to each other have optical axes non-parallel to each other, each optical axis has an angle being not zero relative to the central normal, and a plane including the optical axis and the central normal is perpendicular to a rotational symmetry axis, and an angle between the optical axis and a line normal to the light-receiving surface is smaller than an angle between the central normal and a line normal to the light-receiving surface.