A retardation film according to the present invention consists of a single-layer film in which a birefringent chain polymer is oriented, the polymer having as a repeating unit (A), a structure represented by the following general formula (V): ##STR00001## wherein R.sup.3 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; R.sup.4 and R.sup.8 each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxyl group having 1 to 4 carbon atoms, a linear or branched thioalkoxyl group having 1 to 4 carbon atoms, halogen, a nitro group, an amino group, a hydroxyl group, or a thiol group (where R.sup.4 and R.sup.8 are not simultaneously hydrogen atoms); and R.sup.5, R.sup.6, and R.sup.7 each independently represent a hydrogen atom or a substituent.