A reactor equipped with a feedstock and air injection system has been developed for producing oxidized bitumens. In order to prevent formation of circulation loops in the central zone of the reactor and to intensify the oxidation process and enhance operation efficiency in a wide output range, the reactor is provided with a pulsating stirring device (PSD). The operating principle of the PSD is based on alternate joining of nozzle-fitted hollow cylindrical pulsation chamber placed in the reactor coaxially with the line of injection of compressed air into the reactor and expulsion of the air from the chamber into the reactor. The frequency and duration of pressure buildup in the chamber and expulsion are fixed by the pulsator. High-speed jet flow of the medium from the nozzles ensures alternation of filling of the pulsation chamber with the medium from the reactor and its expulsion.