A polymer compound has a group represented by Formula (1) or Formula (2) in a side chain.(In Formula (1), X1 represents a neutral amino acid residue or an ω-aminoalkanoic acid residue, X2 represents a membrane-permeable peptide residue, X3 represents a hydroxyl group, an amino group, an alkoxyl group having 1 to 4 carbon atoms, or a benzyloxy group, and a represents a number of from 1 to 50.)(In Formula (2), X4 represents a neutral amino acid residue or an ω-aminoalkanoic acid residue, X5 represents a membrane-permeable peptide residue, X6 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a benzyl group, an acyl group having 1 to 6 carbon atoms, an arylsulfonyl group, or a carboxyl group, and b represents a number of from 1 to 50.).
