Patent ID: 7427748

Claim:
A reflection type photoelectric switch comprising: a first casing which has a mounting surface and an opening portion formed so as to face to the mounting surface; a second casing which covers the opening portion of the first casing; an optical system including an optic axis of emitting light and receiving light in parallel with the mounting surface of the first casing, and a light emitting element and a light receiving element, which is disposed in a predetermined area on the mounting surface in the first casing; a light emitting circuit substrate which is disposed in the first casing and has a control circuit of the light emitting element mounted thereon; and a light receiving circuit substrate which is disposed in the first casing and has a control circuit of the light receiving element mounted thereon, wherein one of the light emitting circuit substrate and the light receiving circuit substrate is disposed in an area other than the area on the mounting surface in the first casing in which the optical system is disposed, and the other is disposed so as to be overlapped with at least a part of the optical system, on the opening portion side in the first casing.