Optical switches are indispensable for improving the reliability of optical communication systems and for enhancing the functionality of various measurement devices. As the optical communication technology has advanced, switches have come to occupy an extremely important position. With a view to developing a miniature, low-loss mechanical optical switch, an optical switch is trial fabricated in which the planar optical waveguide is moved mechanically. In this paper, the operating principle and the fabrication process of the newly conceived optical switch are described. In addition, from the measurement of the losses in each section of the optical switch with planar optical waveguide elements and from the simulation of the optical coupling loss, the effectiveness of the optical switch structure is studied. It is found that most of the insertion loss is the propagation loss of the planar waveguide itself and that the increase of loss due to the gap in the optical switch section and to the deformation of the planar optical waveguide at the time of switching is much smaller than the propagation loss of the planar waveguide. Further, an opti-cal switch loaded with an electromagnetic actuator is fabricated for trial. It is demonstrated that self-sustaining switching is possible. From the results of simulation and test, it becomes clear that the loss of the optical switch can be kept below 1 dB if the error of the optical switching stroke is reduced.