PURPOSE: To obtain an inexpensive optical switch of simple structure, of low optical attenuation factor, and of little limitation on where to be used is obtained by operating a moving piece that has a slit, in an optical path connected to an optical input port and to an optical output port respectively.

CONSTITUTION: In the space 5 of a holddown member 1, a slit 8 formed on a switch film part 7 of a moving member 2 is moved, and an optical path between an optical fibers F1 and F2 connected to an optical input port 3 and to an optical output port 4 is turned on or off. In this way, an inexpensive optical switch of low optical attenuation factor, of little limitation on where to be used, and of simple structure can be obtained.