PURPOSE: To facilitate assembling of compressor housing by tapering one end face of axially split housing then inserting a tapered ring while shrinking radially and stopping temporarily thereafter releasing shrinkage and tightening regularly through a bolt.

CONSTITUTION: A tapered ring 102 is arranged between the tapered face at the front side end face 101 of rear member 12 and the rear side face of front member 11. Said ring is radially shrinked through a jig then the front member 11 and the rear member 12 are temporarily tightened through a bolt. Upon recovery through resiliency to release radial shrinkage, said ring is contacted tightly against the rear end face of front member 11 and the tapered face 101 of housing 10. Then the temporarily tightened bolt is further tightened with specific torque to complete assembly.