An optical switch has plural incident side optical fibers 4a; plural main emitting side optical fibers 7a respectively arranged so as to be opposed to the respective incident side optical fibers 4a; a single preliminary emitting side optical fiber 7b; a reflection means 5 moved so as to be positioned with respect to one of the incident side optical fibers 4a, and reflecting an optical signal from the incident side optical fiber 4a to the preliminary emitting side optical fiber 7b; and a driving means 21 for moving the reflection means 5 with respect to each incident side optical fiber 4a and reflecting the optical signal from this incident side optical fiber 4a by the reflection means 5 and able to set this optical signal to be incident to the preliminary emitting side optical fiber 7b. <IMAGE>