To hone a workpiece by the simple movement of a honing tool while holding its compact structure, to reduce the unnecessary facilitates, and to dispense with setup change works when grinding as premachining.

The workpiece W having a cylindrical internal circumference is installed in the front end of a cylindrical main spindle 22 and honed by inserting the honing tool T inside the workpiece W from the rear through an insertion hole in the main spindle 22, while rotating the main spindle 22 and the workpiece W. When grinding it as the premachining, a grinding wheel 20 for inside grinding is inserted inside the workpiece W installed in the main spindle 22 from the front while rotating, and the honing tool is inserted inside the workpiece W from the rear with the workpiece W installed in the main spindle 22 so as to hone it.