The définition of managers social group entity is here considered like a conceptual key for enter the comprehension of the social stratification problematic. The history of his constitution as reference group (the managers), his institutional and political visibility in France are concisely recalled in order that put in foreground, the ambiguous and, sometimes, contradictory caracteristics of appurtenance feeling of his members. The social group of managers (« cadres » in french language) Effectively draw his reference mod and his intragroup categorization form in the twice Weberian ideal types: the status group and the social class. The existence of a hybridization of the democratic and economist model, culturally at the foundation of social group of the managers (and / or of the engineers) by a « hierarchist » ideology is noted. This question is then analysed in his structural and anthropological bases. This theoretical discussion confirms the Boltanski’s interpretations (1982) of the essential function of prototypes in the sociocognitiv construction of such social groups. The same ideological process may it have been to work in other forms of representations of social sets?