An image forming apparatus includes a line head that performs exposure on a latent image carrier to form a latent image. The line head includes first and second light-emitting elements arranged in a first direction; and an optical system that images light emitted from the first and second light-emitting elements. When a difference between the maximum and minimum values of a longitudinal aberration of the optical system is G, a distance in the first direction between centers of geometry of the first and second light-emitting elements is Pel, and an optical magnification of the optical system is β, a relation of G>|β|·Pel is satisfied.