A triarylamine derivative represented by a general formula (G1) given below is provided. Note that in the formula, Ar represents either a substituted or unsubstituted phenyl group or a substituted or unsubstituted biphenyl group; α represents a substituted or unsubstituted naphthyl group; β represents either hydrogen or a substituted or unsubstituted naphthyl group; n and m each independently represent 1 or 2; and R1 to R8 each independently represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, or a phenyl group.