To improve working efficiency by accurately or efficiently polishing a cutter.

This device polishes the cutter by relatively moving a fixed table for fixing the cutter by a fixture by holding the cutter between the fixed table and a fixing plate and a grinding tool slid and contacted by the cutter. The device is provided with a tool for fixing constituted of a fixed table side tool fixed by the fixture by being held between the fixed table and the fixing plate and a cutter side tool mounted on the fixed table side tool to fix the cutter by holding the cutter between the cutter side tool and the fixed table side tool. A positioning mechanism is provided to decide a fixing position of the cutter in relation to the tool for fixing between at least one of the fixed table side tool and the cutter side tool and the cutter.