A kit for dental adhesive comprising a radical polymerizable monomer having an acid group in the molecule, a photosensitizer and/or a peroxide, a water-soluble organic solvent, an organic sulfinic acid and/or a salt thereof or a barbituric acid and/or a derivative thereof, and water. The kit may further comprises a radical polymerizable monomer which has no acid group and is insoluble or hardly soluble in water, an amine compound, a silane coupling agent and a 1,3,5-triazine-2,4-dithion derivative. By using this kit, the adhesive composition can be applied directly to a dentine without conducting a pretreatment.