To efficiently irradiate a surface such as a liquid crystal panel with light by providing an illuminator with a light converting means for converting light from a lamp into a parallel beam and allowing its irradiated area to correspond to the diagonal size of the surface.

A light emitting part 3 is arranged in a reflector 2 constituted of a paraboloidal face in a lamp 1, light from the light emitting part 3 is reflected on the inner surface of the reflector 2 and exits from an aperture part with a diameter a to the front as a parallel beam. A condenser lens 4 is arranged as a converging convex lens in the front of the lamp 1 to converge light from the reflector 2 upon the incident plane of a concave plane lens 5. The lens 5 coverts the light from the lens 4 into a parallel beam capable of irradiating the area of a diameter b and projects the parallel light. The diameter b of the parallel beam projected from the lens 5 is made the length corresponding to the diagonal of a surface such as a liquid crystal panel. Consequently light capable of irradiating an efficient irradiation area on the surface can be formed by the lens 5.