A copolymer includes a repeating unit represented by Formula (I); and a repeating unit represented by Formula (II), in Formula (I), R1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; R2 represents an alkyl group having 1 to 20 carbon atoms and having at least one fluorine atom as a substituent, or a group including —Si(Ra3)(Ra4)O—; L represents a divalent linking group as defined herein; and Ra3 and Ra4 each independently represent an alkyl group as defined herein, in Formula (II), R10 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; R11 and R12 each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; R11 and R12 may be linked to each other; and X1 represents a divalent linking group.