PURPOSE: To continuously perform multiple processes while a work is held by a chuck by providing at least three tool holders on an index table provided positionably in the peripheral direction with respect to a work holding section.

CONSTITUTION: The first through fourth tool holders 16, 17, 18, 19 are fixed at a uniform interval on an index table 15 installed rotatably in the direction of an arrow 14 on the third table body 2a. The rough grinding and finish grinding of the inner periphery 32 of a work W and the finish machining of a pair of one-side faces of a keyway formed to be opened on the inner periphery 32 are performed by the first through fourth tools 28, 29, 30, 31 held by the first through fourth holders 16, 17, 18, 19 while the work W is held by a chuck 3.