To provide a dumbbell, though it has conventionally one usage for mainly training an arm, also having a function of training the wrist and used as two ways by changing over between the training of the arm and the training of the wrist.

A grip part is formed of double structure of a rod-shaped body and a cylindrical shape, the central part of the inner-part rod-shaped body is continued to the central parts of weight parts, the weight part has a disk-shaped double structure, the inside weight part is assembled with a disk-shaped weight part deflecting its center outward and fixed with a bolt fitting so as to rotate around the center by 60° and stop at four positions. The center of the rod-shaped body of the grip part can be changeable to deflect outward from the centers of the disk-shaped weight parts in the both ends.