Acid dianhydride and use thereof

[Problem] To provide a polyamic acid and a polyimide that yield a polyimide film characterized by having low retardation as well as exceptional flexibility and transparency, and a novel acid dianhydride to be used in the production of said polyamic acid and polyimide. [Solution] A polyamic acid obtained by reacting an acid dianhydride and a diamine component, wherein the polyamic acid is characterized in that the acid dianhydride component includes an acid dianhydride represented by formula (1-1); a polyimide that is an imidized product of said polyamic acid; a composition for forming a polyimide film that includes said polyamic acid; a composition for forming a film that includes said polyimide; and polyimide films obtained therefrom. (In the formula, R1 to R5 each independently represent a halogen atom, an alkyl group, or an alkoxy group; R6 and R7 each independently represent a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; a and b each independently represent an integer of 0-4; c and d