An optical switch for switching communication light beams propagating through a plurality of optical fibers. The switch includes a plurality of input-side lenses, a plurality of moving mirrors, a plurality of output-side lenses, light emitting units, and light receiving units arranged for optical communication. The plurality of input-side lenses include first input-side lenses to which communication light beams coming from first external units and propagating through input-side optical fibers connect optically and second input-side lenses to which the light beams from the light emitting units connect optically. The plurality of output-side lenses include first output-side lenses for causing light beams passing therethrough to optically connect to second output-side optical fibers adapted to propagate the communication light beams to second external units and second output-side lenses for causing the light beams coming from the light emitting units and passing therethrough to optically connect to the light receiving units.