The present study investigates microwave irradiation to develop the recycling technology of any kind of plastic waste containing organic chlorine, dechlorination. Polyvinyl chloride (PVC) was used as a typical organic chlorine. Under constant sample temperature, the PVC dechlorination properties were compared between microwave irradiation and conventional heating. It was clarified that microwave irradiation induced much faster dechlorination than conventional heating. It was also found that the dechlorination reaction by microwave irradiation progressed at a lower temperature than that by convention heating. Moreover, the efficiency of dechlorination, defined as the ratio of dechlorination to total weight loss, using microwave irradiation was higher than that by conventional heating. This result shows the possibility of selective dechlorination by using microwave irradiation.