A proximity sensor 717 comprising a combination of an arbitrarily selected one of a plurality of types of detection end modules 707, a plurality of types of output circuit modules 709 and a plurality of types of outer shell cases 711. The detection end module 707 includes an integrated arrangement having a detection coil assembly 705, 701, 702) with the detection characteristic self-completed by a mask conductor 700 for reducing the conductor detection sensitivity in a specific peripheral area where the outer shell case is assumed to exist, and a detection circuit assembly (703) with the coil of the detection coil assembly as a resonance circuit element. The characteristics of the proximity sensor are completely adjusted before shipment. As a result, the adjustment of the characteristics which otherwise might be required each time is eliminated even in the case of the combination with an outer shell case of a different material. Thus, the commodity design and production are facilitated for a great variety of commodity specifications.