To make it possible to obtain gentle elasticity and the touch liable to fit to the palm of the hand by embedding a core material into an elastic part consisting of a soft elastic resin or rubber formed with a rugged surface of a corrugated shape to form a grasping power trainer and specifying the hardness stipulated by A of JIS(Japanese Industrial Standards) of the elastic part to a specific value.

The elastic part 3 formed with the rugged surface of the corrugated shape nearly coinciding with the average sizes and intervals of the fingers on the flanks is formed to a shape which is long in a vertical direction and slightly slender upward. The section in the horizontal direction thereof is formed to an elliptic or oblong shape. The elastic part 3 is formed of a polyethylene gel or silicone rubber and the hardness stipulated by A of JIS is specified to a range of 1 to 20. The core material 4 consisting of the resin or rubber is formed to the outside shape nearly resembling the external shape of the elastic part 3 and is embedded into nearly the center in the elastic part 3. As a result, the elastic part has substantially no bouncing back action and, therefore, the problem that a user suffers from an injury, such as bruise, by the detachment of the trainer from the hand and the strong contact thereof with the body at the time of the resetting action after bending is eliminated.