PURPOSE: To enhance efficiency of surface finishing process for a scroll material by arranging the cutting process on a swirl-shaped side wall of a scroll material in such a way as assigning both a circular motion and an axial shift to either the scroll material or a word tool.

CONSTITUTION: When a swirl-shapee side wall to be used in a scroll type fluid intake/exhaust unit is presicely fabricated, scroll member A with a raw material configuration is fixed on a work stand, while a work tool 100 provided with its cutting blade set on the top of swirl-shaped body is so supported as engaged with the side wall of member A, thereby being shifted from the member A by 180% and its cutting edge being brought in contact with the side wall thereof, and at the same time it is fixed to the work unit so that a circular motion may be allowed. When the work tool 100 is allowed by its work unit to make a shifting movement along the swirl-shaped side wall of member A as well as a circular motion, surface finishing work on member A can be accomplished in a short time with high accuracy, resulting in achievement of productive means of fabrication.