To avoid the adverse influence of overpressure which accompanys the temperature rise and is applied to the valve seat of a pressing plug valve and to prevent the deformation or damage of valve rubber and the valve seat, in a pressure regulating device which has a lever type pressing stop valve.

The pressure regulating device 1 has a regulating rod 4 which interlocks with the movement of the pressure plate of a diaphragm 2a, a lever 5 and a pressing stop valve which interlocks with the movement of the lever 5. It form a hollow tube part 9 in a valve rod 7 of the pressing stop valve that interlocks with the lever 5, has valve rubber 12 that is attached to a valve rubber holder 11 which is energized by a holder spring 10 in it and whose moving amount is limited by a holder stopper 13, further forms valve rod stopper plane 14 on a valve seat side, presses the valve rubber against the valve seat with a fixed pressure by a valve rod tip touching on the stopper plane, and absorbs excessive pressed pressure that is applied to the valve rubber by the spring inside the valve rod.