The high pressure gas inlet channel (6) of the pressure regulator (1) is formed upstream in a stationary valve element (7) having an enlarged terminal head (9) interacting with a seat edge of a movable seat (10) acted upon in closure position by a spring (23), the mounting of the pressure regulator (1) in the high pressure gas inlet tap body (3) causing the retraction of the seat (10) and the opening of the inlet channel normally kept blanked off during operations of storage and/or washing of the pressure regulator.Applies mainly to sea diving pressure regulators.