To provide an exercise tool for chewing well, which can be used repeatedly and safely over a comparatively long period of time and has good appearance in wearing and using it.

This exercise tool 1 is worn on the lower teeth along the dentition to be used. The tool is formed by a locking part 3 formed substantially U-shaped to cover the back of the teeth and a protective part 5 connected to both right and left end parts of the locking part to cover at least the occlusion surfaces of right and left molars. At least the right and left protective parts are formed of elastic material such as a silicone resin, or the like, having elastic force to be elastically deformed by chewing of back teeth, and restored to the initial state by release of chewing.