An acid anhydride of the formula (4), and a polyimide using the acid anhydride, ##STR00001## wherein anhydrides are substituted at sites 3 or sites 4, which acid anhydride is obtained from, as a raw material, a bifunctional phenylene ether oligomer having a number average molecular weight of 500 to 3,000, represented by the formula (1). ##STR00002##