Disclosed are: a phosphate ester compound having an unsaturated double bond and a metal salt thereof; a dental material comprising at least one member selected from the phosphate ester compound and/or the metal salt thereof; and a dental composition comprising a polymerizable compound and a polymerization initiator, wherein the polymerizable compound has the unsaturated double bond and/or a salt thereof. The phosphate ester compound enables to provide a dental material or a dental composition such as a bonding material, an adhesive/cohesive material having excellent storage stability, easy to handle, and having a higher adhesion property and higher adhesion durability.