PURPOSE: To propose a disk tool for a hand-carrying driving device capable of surface machining not only in the outer circumferential region but also on both side surfaces.

CONSTITUTION: This disk tool 8 for a hand-carrying driving device has abrasive grains on its outer circumferential part 8e and side face surfaces 8a, 8b, and is provided with an annular-disk-shaped support body whose central part has a through hole 31 for fixing the disk tool to the driving device. By forming this support body in a cone tapered shape symmetric in relation to the center direction in the through hole region, engagement surfaces 8c, 8d engaged with an attachment element 11 for fixing the disk tool 8 in an tool holder 7 are formed. The tool holder 7 is arranged not to overlap with the side face surface 8b of the disk tool 8.