The aim of this study was to compare four time‐zone activity rates over 24 h between melancholy type major depression (MMD) patients and normal subjects using actigraph. Ten patients diagnosed as suffering from MMD in the hospital attached to the Kinki University were the subjects of the present investigation. Another age‐matched group of 10 normal healthy subjects with an approximate sex ratio were taken as controls. Subjects were each asked to consistently wear an actigraph on the wrist from the day of admittance to the day of discharge from the hospital, while the control group wore similar actigraphs over a 1‐week period. Immediately after initiation of therapy (initial phase) for MMD (day 2 after admittance), until the relief phase (1 day before discharge), circadian activities were monitored with actigraphs at four time zones over a 24‐h period: 06:00–12:00, 12:00–18:00, 18:00–24:00 and 00:00–06:00 hours. In the control group, similar procedures were followed to obtain parallel data. In the comparison of MMD patients with controls in the initial phase, the activity rates of the MMD group in the 12:00–18:00 hours zone were significantly higher than the control activity rates, and those of the 18:00–24:00 hours zone were lower than the control. When activity rates in the initial phase were compared with the relief phase in MMD patients, those of the initial phase were higher than the relief phase at 12:00–18:00 hours. In the disease‐stage of MMD, activity rates of time‐zones 12:00–18:00 hours are relatively high in affected patients. Based on actigraphy, an objective therapy criterion for assessing MMD may plausibly be established.