The present invention provides a polymerizable composition that exhibits excellent adhesive properties to a tooth structure (particularly dentin) when applied as a dental material, and a polymerizable monomer that is used as a component of the polymerizable composition. The present invention is a polymerizable monomer (A) that is a compound having at least two polymerizable groups. The polymerizable monomer (A) has a retention time of 7 minutes to 30 minutes in a high-performance liquid chromatography (HPLC) measurement conducted under a condition in which a column with an inner diameter of 3.9 mm and a length of 300 mm, packed with a C18 packing material having been crushed to have an average particle size of 10 .mu.m and a pore size of 125 angstroms, is used, an eluent is a mixed solvent of methanol and water contained at a ratio of 3:7, a flow rate is 1.0 mL/minute, a measurement temperature is 50.degree. C., a sample injection volume is 10 .mu.L, and a dead volume from a sample inlet to a detection point excluding the column is 87 .mu.L. The present invention also is a composition containing the polymerizable monomer (A).