The problem of the conceptual maintenance of the psychological mechanism is delivered. Are disassembled a semantic field and concept "mechanism" determination. It is raised the question about a place and a "mechanism" role in scientific and methodological judgment of natural, social, psychological phenomena; need of specification of determination of the psychological mechanism is shown. Methodological paradoxe of "mechanism" are formulated. Two various etymological roots of the concept "mechanism" are tracked. Thanks to that "nature" of the mechanism originates from two inconsistent sources, its explanatory force isn't limited to any one subject domain, and extends on various objects of scientific knowledge, including on area of methodology of science. In article it is shown how the psychological mechanism causes the constant appeal of psychological thought to the nature of communication of elements of psychological experience.