An expert system to be used in automatized psychodiagnostic studies is described. From similar computerized systems this one differs in two respects: (I) It has two subsystems - instrumental and testing ones; the former is to be used in design of testing subsystems, while the latter is a means of automatization of the psychological experimentation. (2) Automatic processing of raw data and consequent interpretation of results of psychological study are based on use of the professional knowledge.