PURPOSE: To improve machining accuracy of a stator by taking an inner bore profile or a stator for a pump or a motor with an eccentric shaft as outer machining surfaces, manufacturing it by dividing machining, disassembling in the longitudinal direction, and assembling a complete inner bore profile.

CONSTITUTION: In manufacturing a stator for a pump or a motor with an eccentric shaft, particularly, an extended stator, segments of an inner bore profile 14 of a stator 1, to be formed on the rod-like work pieces 3, 3' are taken as outer machining surfaces AF1, AF2, AF3 and AF4 and manufactured by cutting. The workpieces 3, 3' are longitudinally divided into the specified number of partial workpieces so that all partial workpieces 3a1, 3b1, 3a2 and 3b2 may have one segment of the inner bore profile 14. The partial workpieces 3a1, 3b1, 3a2 and 3b2 are so assembled that the segments may form the complete inner bore profile 14.