PURPOSE: To provide a proximity switch of such a structure that a printed circuit board on which electronic parts and circuits are mounted, is accommodated in a case and internal space thereof is filled with insulative resin, wherein the electronic parts mounted on the printed circuit noard are protected against thermal stresses in the insulative resin.

CONSTITUTION: Electronic parts 3A and electronic circuit 3B on a printed circuit board 4 to be accommodated in the case 1 of a proximity switch are sealed in by attaching an insulative tape 9 having flexibility and pressure sensitive adhesiveness to the printed circuit board 4.