A case is presented who has recovered from depressive neurosis by the photic feedback (PFB) therapy. The PFB system was developed in order to make body and mind relaxed by enhancing alpha waves of electroencephalogram (EEG) utilizing light signals made from subjects' own EEG. The patient was a 61-year-old male who had developed depressive neurotic symptomatology including insomnia, depressed mood, irritability and gastralgia five years before the first visit under stressful situations accompanying an annexation of his company and suicide of its president. His symptoms had persisted since then because he had been experiencing various distressful life events such as his wife's suffering from subarachnoidal hemorrhage, his symptoms including chest discomfort and palpitations diagnosed as 'angina pectoris', and death of his father and one of his classmates. We have treated this case by using PFB system following the A-B-A-B single-case experimental design. A questionnaire was used as psychological indices measuring depressive mood, cognitive and perceived physiological aspects of anxiety and irritability. Various physiological measures were also monitored such as EEG, skin surface temperature (SST), skin conductance level (GSR), plethysmogram (PLE), the coefficient of variance of the component of respiratory related sinus arrythmia (CCV-HF) and Mayer wave related sinus arrythmia (CCV-LF). Scores of psychological indices, especially depressive mood, decreased within each session until the middle period of the whole treatment. Increases of SST and CCV-HF were also observed, and these psychological and physiological changes were consistent with the state of relaxation. Sleep disturbance such as talking and roaring out during his sleep was improved after one session. and depressive mood was also improved in the first half of the treatment. However, depressive mood was again aggravated and intense anxiety about cardiac illness also appeared in the latter half of it because his close relatives and friends died one after another then. His conditions began to get better after we added cognitive interventions and extended feedback time of the therapy against this situation. We terminated the PFB therapy in the 41 st week. It is hypothesized that the efficacy of the PFB therapy is derived from relaxation induced by alpha wave enhancement. However, how alpha wave enhancement induces relaxation or what relaxation really is still remains to be elucidated. What kind of illnesses can be effectively treated by the PFB therapy should also be made clearer in the future.