Red light emitted from a red laser light source, green light emitted from a green laser light source and blue light emitted from a blue laser light source are incident on a first disc body of a color wheel, are transmitted or reflected in conformity with the colors of the lights in wavelength selecting regions of a second disc body every time the color wheel performs a predetermined rotation. AS being reflected by the first disc body, the lights are divided into different positions to be emitted from the color wheel and irradiated to irradiation regions successively switched by an upward or downward reciprocal movement of a mirror group.