Patent ID: 8376529

Claim:
A pressure-regulating valve for opening and closing a valve body provided to a communication flow passage via which a primary chamber and a secondary chamber communicate inside a valve housing, with the aid of a pressure-receiving membrane that constitutes one surface of the secondary chamber, for regulating the pressure of a liquid fed to the primary chamber via an inflow port, and feeding the liquid from the secondary chamber via an outflow port, wherein an internal wall of the secondary chamber facing the one surface comprises: a flat wall portion with a secondary-chamber-side opening of the communication flow passage being formed in the center portion thereof; a conforming wall portion with which the pressure-receiving membrane makes conforming contact upon being deformed, the conforming wall portion including an annular flat wall portion and an annular tapered wall portion with the annular flat wall portion being connected to the outside of the flat wall portion via a step portion, the annular tapered wall portion being connected to the outside of the annular flat wall portion, and the annular flat wall portion having an outflow opening communicated with the outflow port formed at the bottom of the conforming wall portion; and an extending groove portion extending upward from the flat wall portion to cut into the conforming wall portion so as to traverse the annular flat wall portion in a radial direction.