To provide a pressure regulator whose cost can be reduced by simplifying the mechanism, and whose response to change of gas consumption can be quickened.
In this pressure regulator, a gas inflow passage 11 is connected through a main passage 19 and a sub-flow-passage 12 to a gas outflow passage 18, and the sub-flow-passage 12 is approached through a throttle part 13 and a spring chamber 15 of a differential pressure operating diaphragm 14 and a pressure adjusting valve 17 to the gas outflow passage 18, and the main passage 19 is approached through a main valve mechanism 20 operating by the differential pressure operating diaphragm 14 to the gas outflow passage 18. The differential pressure operating diaphragm 14 is directly formed with the main valve mechanism 20, and the sub-flow-passage 12 is approached from the gas inflow passage 11 to the spring chamber 15 of the differential pressure operating diaphragm 14, and the sub-flow-passage 12 is formed with an orifice being the throttle part 13, or the support part of the differential pressure operating diaphragm 14 is formed with a small hole so that the gas inflow passage 11 and the spring chamber 15 of the differential pressure operating diaphragm 14 can be turned to be a communicating state.
