an improved photoelectric switching device for coordinate detection system comprises a first array of light emitting elements , a first array of photo - detecting elements for receiving the light from the first array of light emitting elements and producing a first block signal when the light is blocked by a stylus , such as a finger , a second array of light emitting elements , a second array of photo - detecting elements for receiving the light from the second array of light emitting elements and producing a second block signal when the light is blocked by the stylus wherein the light receiving surfaces of the second array of photo - detecting elements are aligned an angle , such as 180 degrees , with respect to those of the first array of photo - detecting elements , and a control means such as a microcomputer for driving the first and the second array of the light emitting elements and for discriminating the coordinates of the stylus on the display unit which displays a pattern having several regions allocated for certain control of optional equipment . therefore , the stylus can be detected even if there is an inadvertent operation in either of the first and the second photo - detecting elements due to a strong incidence of ambient light in the lateral direction .