Disclosed is a pressure/flow rate control valve comprising a pressure-adjusting section having a valve plug for reducing the pressure of a pressure fluid flowing through a clearance between a hole and itself, a stem which is displaceable integrally with the valve plug and which is installed with a packing, and a spring member which is fastened to one end of the stem, for pressing the valve plug toward an annular projection formed on an inner wall surface of a first valve body.