A crosslinking agent includes a compound represented by the following formula (1). wherein R1, R2, and R3 are independently a hydrogen atom, a fluorine atom, an alkyl group, a fluoroalkyl group, or a substituted or unsubstituted aryl group, a plurality of R1 are identical to or different from each other, a plurality of R2 are identical to or different from each other, a plurality of R3 are identical to or different from each other, provided that at least one of R1, R2, and R3 is a hydrogen atom, and at least one of R1, R2, and R3 is a fluorine atom or a fluorine atom-containing group, m is an integer from 2 to 6, l is an integer from 0 to 2, and each hydrogen on the benzene ring(s) may be substituted.