A dentin mineralizing agent comprising tetracalcium phosphate particles (A) and an alkali metal salt of phosphoric acid (B), wherein the dentin mineralizing agent contains the tetracalcium phosphate particles (A) in an amount of 1 to 80 parts by weight relative to 100 parts by weight of the whole amount of the dentin mineralizing agent, and the blended amount of the alkali metal salt of phosphoric acid (B) relative to 100 parts by weight of the tetracalcium phosphate particles (A) is 1 to 100 parts by weight. Thus is provided a dentin mineralizing agent by which a dense HAp is formed on a dentin surface and HAp is deposited to a deep portion of a dentinal tubule, so that it can close the dentinal tubule.
