A hand-operated pressure regulating valve for compressed air guns includes a basic valve body with a nozzle passage, threads for connection to a compressed air gun and a nozzle body, a pressure regulating unit and an actuating ring. The regulating unit is held by the ring, with a securing ring, in a bore of the basic valve body. The nozzle passage can be bridged and closed within the bore by a nozzle passage piece. The cross section of the nozzle passage can be reduced and increased by rotation of the ring and displacement of the regulating unit and the passage piece. The regulating unit has a basic body with the passage piece, a spring pin and a compression spring and, in the installed state, the pin projects through the spring out of the basic body and the bore for radial movement transversely and, by rotation of the actuating ring, latches in succession into wells in an inner surface of the actuating ring.