It was made an study about Brazilian Army under the perspective of institutional transformations were operated in its interior in last three decades and about que work of conservation of values what the Military Institution implemented with the goal of preserving its ethos and its identity. The first part talks about the transformation as a value, the military family has been analysed as a factor that promoted deep transformations in Institution. It was observed the fact that the family, at the same time it is part of the internal public of the Army, it also integrates the others institutions of broad society, so being influenced by them. Consequently, family conducts inside to the Institution new transformation ideas that are in the outside of military field. The sample analysed was the group of officers graduated by Academia Militar das Agulhas Negras (Military Academy of Agulhas Negras) – AMAN. Influences were analysed that, coming from the broad society, were exercised over AMAN officer through his family since his formation as a cadet, as also in his combat arm choice, and others that interfere in the quality of the development of his carreer that, being progressively modified, promotes transformations in Institution itself. It was observed that, so, the family of the military has the role of an interface between Army and broad society. The second part shows the importance of the transformation through the conservation movement undertaken by the Brazilian Army for preserving its characteristics considered essential. It was analysed the way like the AMAN officers see themselves besides broad society and the concepts that, like they consider, composed the military ethos: the tradition and the authority, and how these concepts happen inside military field. The third part presents a synthesis of the two lately itens. It presents the institutional way of the Army besides the movements of transformation and conservation that realize its social environment, internal or external; how it constitutes itself sociologicaly as an institution and its challenges that were faced in these days of fast transformations.