Abstract : This thesis is a contribution to the field of psychosocial risks at work. It reports how, in order to respond to the command of an international corporation of electrics industry, we entered the question of psychosocial risk at work, and how we managed to reverse the question. We 've been studying, in a team managers' group, the psychosocial tools used in order to build and maintain health at work. in the perspective of Clinic of Activity, we know firstly that the development of " power to act " in activity protects and promotes health at work, and secondly that the creation of new goals is a medium of this development. That is why , in this research project, we aimed to understand the creation process of new goals in activity, and we studied this process in a specific frame : in and by the way of dialogues about work activity among professional peers. Discourse analysis permit to identify three different processes, a language process and two psychological ones, that all participate to a renew of goals. Those processes are : 1) a new iteration, in the discourse, of a verbal statement taken from another discourse ; 2) the differentiation of goal's origins ; and 3) the elaboration of new links between activities. Those issues allows us to define some of the significant properties of dialogue as a tool for health promotion between peers at work.