Abstract: A scroll type fluid machinery with spiral wraps set up on inner surfaces of end plates, respectively. The spiral wraps are engaged with each other at a predetermined angle dislocation and are housed in a housing with an opening in one end of a cup-shaped casing. This opening is blocked with a front case. The stationary scroll is fixed to the cup-shaped casing, and the revolving scroll is made to revolve in a solar motion by a revolution drive mechanism while checking the rotation on its axis by a mechanism for checking rotation on its axis. In an assembling method thereof, positioning portions are engaged with a positioning jig provided in the stationary scroll and the cup-shaped casing, respectively, and the positioning portions are utilized. With this machinery and method, the number of parts, working time and assembly time are reduced and the manufacturing cost may be cut down.