To provide a method and a device for chamfering a plate-like work capable of prolonging the service life of a grinding wheel, performing the continuous operation of a working machine, and improving the production efficiency.

The axis O of rotation of a rotary grinding wheel 2 is inclined in a plane parallel to an end face 1a to be chamfered of the plate-like work 1 around a contact point C of an annular groove 2a with an end face 1a to be chamfered of the plate-like work 1, a groove bottom surface 2a1 of the annular groove 2a is pressed against the end face 1a of the plate-like work 1, and both inner surfaces 2a2 and 2a3 of the annular groove 2a are pressed against face and back sides 1b and 1c in the vicinity of the end face 1a of the plate-like work 1 so as to apply a small bending moment to perform the chamfering.