Continuous devulcanization by shear flow stage reaction control technology for vulcanized rubber has been developed. Screw geometry and alignment, screw rotation, reaction temperature, internal pressure, and addition of process oil and devulcanizing agent are the most important factors for this process. This process can be applied to sulfur vulcanized rubbers such as EPDM, NR, SBR and IIR. This paper described the results of the devulcanization of EPDM rubber. The obtained devulcanized rubber was found to be even mixture of two components; one is linear chain which is soluble in toluene and whose average molecular weight is nearly equal to that of the original raw rubber, and the other is very loosely crosslinking network whose effective network chain density is about one twentieth of that of the virgin vulcanized rubber. The devulcanized rubber can be revulcanized by conventional curing process with sulfur-accelerator vulcanizing system. The revulcanized rubber exhibited excellent mechanical properties and formability nearly equal to virgin vulcanized one.