PROBLEM TO BE SOLVED: To provide a polymer film in which fluctuation of Re and Rth accompanying humidity change of a use environment is reduced.SOLUTION: The polymer film contains at least one of a compound represented by general formula (I) or a hydrate, a solvate, or a salt thereof (in formula, Y represents a methine group or a nitrogen atom; each of Q, Q, and Qrepresents a single bond or a divalent linking group; each of R, R, and Rrepresents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a cyano group, a halogen group, a heterocyclic group or the like; Xrepresents a single bond or a divalent linking group; Xrepresents a single bond or a predetermined divalent linking group; each of Rand Rrepresents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group or the like; however, one of Q-Rand N(XR)XRis -NHbut two of them are not simultaneously -NH, and when Y is a nitrogen atom and N(XR)XRis -NH, -Q-Ris not -NH).
