The purpose of the present invention is to provide a retardation film which has high retardation developability, good mechanical strength and good durability. This retardation film contains a cellulose derivative and at least one compound represented by general formula (1), wherein each of R1 and R2 independently represents an alkyl group, a cycloalkyl group, an aryl group or a heterocyclic group; X1 represents a single bond, —NR4—, —O— or —S—; X2 represents a single bond, —NR5—, —NR5—(C═O)—, —O— or —S—; each of R4 and R5 independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or a heterocyclic group; R3 represents a substituent; n represents an integer of 0-4; and when n is 2 or more, a plurality of R3s may be the same or different and adjacent R3s may be joined together to form a ring).