To improve insulating performance without making a pressure switch and a thermostat large in size.

In the pressure switch or the thermostat in which by installing a switch part S having a pair of terminals 11, 12 in a resin base member 1 having the peripheral wall part 14 in the whole periphery, by covering a resin made middle cap 2 on the terminal 11 side of a movable side of the switch part S, by placing a metallic reversing disc 5 on the outside of that middle cap 2, and by reversing the direction of the reversing disc 5 to a switch part S side, the middle cap 2 pushes the terminal 11 of the movable side and the paired terminals 11, 12 are made to contact or separate, at the outer peripheral part of the middle cap 2, an annular protruding part 13 surrounding the switch part S by protruding to the switch part S side is installed at the whole periphery. Since the annular protruding part of the middle cap 2 and the peripheral wall part 14 of the base member 1 make an insulation distance between the switch part S and the reversing disc 5 and a cap 10 longer, its insulation performance can be improved without making the device large in size.