To efficiently and accurately conduct internal peripheral grinding composed of plural processes.

Plural inside-grinding grinding wheel units 3, 4 are installed so as to match with auxiliary shafts χ1, χ2, symmetrical with respect to a basic center line X-X. A rotary type index table 1 having the basic center line as a rotating axis is installed, and main shaft units 6, 7 for chucking a workpiece are respectively opposed to the inside-grinding grinding wheel units 3, 4. Different kinds of rotating grinding wheels are respectively attached to the inside- grinding grinding wheel units, thereby conducting grinding of different processes. If rotating the index table 1, the main shaft units 6, 7 are reversed, and the chucked workpieces are replaced to each other. Therefore, machining processes are successively advanced.