Complex regional pain syndrome (CRPS) is a disease that causes chronic spontaneous pain and hyperesthesia of one or more parts of legs and arms, which is accompanied with problems of the automatic nervous system or the motor nervous system. However, up to date, it is unclear what causes the syndrome and how to diagnose and treat it. Although several treatments including medication and sympathetic nerve block are performed against CRPS, the therapeutic effect of the treatments is limited. The electroconvulsive thera-py (ECT), of which the mechanism is not clarified, is a treatment used for treatment-resistant depression. ECT is also reported to be effective against pain. Therefore, we performed the ECT for a 24-year-old female patient who has been diagnosed as CRPS. Her pain had not been much improved by medications and interventional procedures. At admission to a psychiatric ward for ECT, she com-plained of over 8 points of pain on visual analogue scale and the constrained movement around the painful part. Eight ECTs-three times a week-were performed for three weeks in hospital and then the ECT once a week was performed after her leaving the hospital. During the ECTs, pain had been reduced and the range of movement in the constrained parts had increased. Further systematic re-search is needed to confirm the effect of electroconvulsive therapy against CRPS.