The purpose of the present invention is to provide a polymer which is soluble in an organic solvent with low polarity and has high hole injection efficiency without addition of dopant for improving hole injection efficiency. For fulfilling the purpose, a vinyl monomer is disclosed which is represented by the general formula (1) below. In the formula, X represents either an oxygen atom (O) or a sulfur atom (S), and Y represents a hydrogen atom, an alkyl group, an aryl group, or a silyl group which has an alkyl group or an aryl group as a substituent.