To provide a safety tooth hardening piece which feels extremely soft when chewing while keeping a solid object as an object to be chewed similarly to a soft food for a baby.

The tooth hardening piece is provided with a part 11 (12, 13 and 14) for a user to chew by being taken into an oral cavity of the user. The part to be chewed comprises a soft layer 22 consisting of a quality of material extremely soft to a degree which can keep a molded shape and protection layers 21 and 23 which are more rigid than the soft layer and which is deformable. The soft layer is covered with the protection layers.