A photo-switch having a switch case, a plurality of photo-transmissive bodies inserted into the switch case with their ends arranged in a side-by-side relation, and an intermediate photo-transmissive body or a reflecting member carried by a switching means. The switching means is operable to move the ends of the intermediate photo-transmissive body or the reflecting member into and out of optical connection with the ends of the plurality of photo-transmissive bodies thereby to selectively interrupt the transmission of light between the photo-transmissive bodies. When the intermediate photo-transmissive body or the reflecting member is moved away from the ends of the photo-transmissive bodies, a light shielding member is brought into the gap therebetween to improve the resolution of the photo-switching operation.