PURPOSE: To provide a flexible grinding wheel being economical and having a long life capable of preventing partial damage due to stress concentration to a radial groove while preventing a grinding fluid from its discharge to the outside due to the radial groove, in the grinding wheel mounted on an exclusive power tool to be used.

CONSTITUTION: In the grinding wheel formed with a plurality of grinding wheel pieces 2 kneading abrasive paricles of diamond or the like in a surface of a flexible member consisting of natural or synthetic resin or the like, the fellow grinding wheel pieces 2 are arranged with a slight space, and a groove 3, formed of this space, is formed not in a radial shape leading to the outside from the center.