The present invention provides a novel polymer that can impart a moisturized feeling to the hair and skin after use. A polymer comprising an amphoteric monomer represented by the following general formula (I) and a cationic monomer represented by the following general formula (II) as the essential constituent monomers:

(wherein, R₁represents a hydrogen atom or a methyl group; R₂and R₃each independently represent an alkyl or alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a phenyl group, or a â€”(CH₂CH₂O)_nR₇group (n is an integer of 1 to 50; and R₇represents a hydrogen atom or an alkyl or alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a phenyl group); R₄represents an alkylene group having 1 to 3 carbon atoms; A represents an oxygen atom or NR₈(R₈represents a hydrogen atom or an alkyl or alkoxy group having 1 to 4 carbon atoms, a phenyl group, or a â€”(CH₂CH₂O)_nR₉group (n is an integer of 1 to 50; R₉represents a hydrogen atom, an alkyl or alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a phenyl group)); and B represents an alkylene group having 1 to 4 carbon atoms), and

(wherein, R₅and R₆each independently represent a hydrogen atom or an alkyl or alkoxy group having 1 to 4 carbon atoms; and Y^âˆ’ represents a monovalent inorganic or organic anion).