The invention provides a retardation film, composed primarily of an acrylic polymer, with transparency, heat resistance, and large retardation. The retardation film of the present invention is composed primarily of an acrylic polymer. The film has an in-plane retardation of from 130 nm to 500 nm, inclusive, per 100 μm thickness at a wavelength of 589 nm. The film has a total light transmittance of not less than 85%. The retardation film has a glass transition temperature of preferably from 110° C. to 200° C., inclusive. The acrylic polymer, which is the primary component, preferably has a lactone ring structure.