This paper discusses three mediation concept approaches and, consequently, three facets of mediator action.  The approaches presented start with a bibliographical review of the concept of mediation present in education and scientific communication studies.  These approaches serve as a basis for interpreting a semi-directive interview with the director of the Museum of Morphological Sciences of the Federal University of Minas Gerais (UFMG).  They also help us reflect on the complexity of organizing the objectives of a museum action that takes into account the transformational role of the meaning of objects in interaction with different socio-cultural subjects.  In conclusion, the museum's purpose in organizing a museum action using socio-cultural mediation approach and with the mediator as a passeur libre among exhibit objects and visitors is highlighted.