PURPOSE: To make it possible to project light beams with high parallelism and to improve the using efficiency of light by providing the projector with a light guiding pipe capable of linearly expanding light beams converged upon one point in accordance with the advance of the light along the optical axis.

CONSTITUTION: The projector is provided with a light source 10 having a fine light emitting size, a converging optical system including a mirror 20 for converging light beams from the light source 10 upon a point on the optical axis L and the light guiding pipe 30 for guiding the light converged upon one point in the direction of the optical axis L and linearly expanding the light in accordance with the advance of the light along the optical axis L. Thereby, light beams radiated from the light source 10 having the fine light emitting size are converged upon one point by the converging optical system such as a mirror 20 and the converged light is repeatedly reflected by the pipe 30 linearly expanded along the optical axis L, so that approximately parallel light beams can be obtained. Consequently, light with high parallelism can be projected, the using efficiency of light can be improved and the uniform illuminance distribution of an irradiated face can be obtained.