Abstract
Economic Sociology has heretofore contributed to the understanding and explantion of economic phenomena, from the viewpoint of the social systems theory, or based upon the assumption of non-economic motivation to action. This paper, apart from these traditions, shows that it is not possible to explain modes of market transactions, which is the core of economic phenomena, without sociological factors, when uncertainty matters, even if they are composed of actions motivated entirely by economic interests. Trust in transacting relationships of subcontracting or in industrial districts are examined as examples.
