To save a space by providing a first block body possessing a primary pressure input port and a second block body possessing a secondary pressure output port in a pressure governor main body and allowing relative rotation of both block bodies.

A pressure governor main body 5 is provided with a substantially cylindrical first block body 80 possessing primary pressure input ports 81a, 81b and a substantially cylindrical second block body 70 possessing a secondary pressure output port 75. The block body 70 is put on the block body 80, and an O-ring 69 is arranged between them for maintaining airtightness without disturbing their mutual rotational motion. For connecting the block bodies 80, 70 together, ring type grooves 73, 83 are formed in the fitting part between them, and a connection ring is inserted from the outside to a ring type hollow part formed by integrated ring type grooves 73, 83, so that the block bodies 80, 70 can be surely connected together. Therefore, an input port and an output port can be surely connected to piping positions with ease even if the piping positions are restricted, so that a space can be saved.