A light source unit includes one or more light source rows that include a first light source row including light emitting devices. The light emitting devices of the first light source rows are arranged at non-uniform intervals. An illuminator includes a light source unit for emitting a bundle of light beams, a first fly-eye lens including lenslets, a second fly-eye lens, and a condenser lens. The light source unit includes one or more light source rows each including light emitting devices. The principal rays of first light beams outputted from a first light source row out of the one or more light source rows enter different lenslets out of the lenslets. A positional relationship between a principal ray of each of the first light beams and the optical axis of the lenslet which the principal ray enters is aperiodic over the first light source row.