<p>An optical switch using a vibration-resistant mirror having a high reflectance. The optical switch comprises an optical waveguide substrate (230), a mirror portion (118) and a movable portion (231) on which the mirror portion (118) is mounted. The mirror portion (118) has a light-reflecting portion (101) and a supporting portion (102) for supporting the light-reflecting portion (101) on the movable portion (231). The optical waveguide substrate (230) has a groove (247) into which the light-reflecting portion (101) is inserted by the movable portion (231) for switching over the optical path, and a recess (250) for receiving a part of the supporting portion (102) when the light-reflecting portion (101) is inserted into the groove (247).</p>
