PURPOSE: To polish each blade portion of a chain saw blade efficiently and at constant angles by forming the abrasive surface of a polishing grindstone into a shape according to at least three blade faces of the each blade portion to be polished and thereby polishing the blade faces at once.

CONSTITUTION: The angle of a polishing grindstone 28 is adjusted by a fitting seat plate 23, the height by adequate rotation of a guide pole 16, and the swing range by the stopper screw of a stopper arm. With a drive motor 25 rotated to rotate the grindstone 28 and with an operating arm 21 swung with an operating cylinder 18 as a fulcrum, the grindstone 28 is displaced toward a guide member 6 while rotating with the arm 21, and polishes at once the three faces of each blade portion W' held by the guide member 6. Thus, each blade portion of a chain saw blade can be polished efficiently and at constant angles.