To provide an adapter device provided with a structure capable of mounting and dismounting a honing tool on a rotary main shaft of a honing panel simply and speedily without causing swing due to rotation.

This adapter device for honing tool is provided with a holder holding part 5 provided in a tip part of a rotary main shaft 2, a tool holder 6 which holds a honing tool 1 integrally and is inserted and fixed in a shank holding hole 20 of the holder holding part 5 so as to remove it, and a chuck fixing part 7 engaging and fixing the tool holder 6 and the holder holding part 5 so as to engage and disengage them. The chuck fixing part 7 is provided with an engaging mechanism 40 engaging both of the holder holding part 5 and the tool holder 6 so as to engage and disengage in the axial direction due to relative rotary operation around a shaft core of both of them 5, 6, an engaging position determining part 47 locking and fixing the relative rotation around the shaft core of the holder holding part 5 and the tool holder 6, and a chuck mechanism 45 chucking and fixing an engagement condition by the engaging mechanism 40 due to relative travel of the holder holding part 5 and the tool holder 6 in the axial direction by a rotary operation part 56.