To provide a new antioxidant, active oxygen scavenger and free radical scavenger.

This antioxidant comprises a pyrrolopyrrole derivative represented by the following general formula [I] (wherein, A1 to A10 denote each independently hydrogen atom or an alkyl group which may have a substituent) or its salt. The antioxidant is used not only as the antioxidant, an oxidation inhibitor, etc., but also as an active oxygen and/or a free radical scavengers. A pharmaceutical composition comprises the pyrrolopyrrole derivative represented by the following general formula [I] or its salt and a pharmaceutically acceptable carrier. Furthermore, a healthy food comprises the pyrrolopyrrole derivative represented by the general formula [I] or its salt.