Analyzing S.L.Rubinstein's subject-activity conception by following A.V.Brushlinky, we have confirmed the importance of the concept "subject" in the activity theory. From the viewpoint of the subject-activity conception, it is clear that both A.N.Leont'ev's activity theory and M.Cole's cultural-historical activity theory underestimate the role of the subject of activity. The problem of the subject is the touchstone for the humanity of psychology.
