Device for heating and/or cooling a vehicle provided with an inner floor, including a supporting structure, at least one elongate structural element fixed on said supporting structure and an inner floor comprised of inner floor elements fixed on said elongate structural element, wherein: a) said elongate structural element comprises a profile member which is made of a heat-conductive material and which has an upper bearing surface, substantially horizontal and oriented upwards, intended for supporting said inner floor elements; b) each inner floor element comprises an edge made of a heat-conductive material which has a lower bearing surface that is substantially horizontal and oriented downwards, intended to be placed on said upper bearing surface of said profile member and a heat-conductive layer which extends substantially over the entire extent of said inner floor element; c) when said inner floor element is placed on said profile member for the purpose of the fastening thereof, said lower bearing surface of said inner floor element and said upper bearing surface of said elongate structural element are connected to one another by means of one or more contact surfaces; characterised in that: d) said elongate structural element also comprises a heating and/or cooling unit, which is connected to said profile member by means of one or more contact surfaces ensuring good thermal conductivity between said heating and/or cooling unit and said profile member and which is arranged with respect to said profile member in such a way that the thermal fluxes generated by said heating and/or cooling unit are transmitted by said elongate structural element to heat or to cool the ambient air present inside said vehicle; e) said heat-conductive layer belongs to the same part as said edge or is connected to the latter by means of one or more contact surfaces ensuring good thermal conductivity between said edge and said conductive layer; f) said contact surface or surfaces ensure good thermal conductivity between said inner floor element and said profile member. a) said elongate structural element comprises a profile member which is made of a heat-conductive material and which has an upper bearing surface, substantially horizontal and oriented upwards, intended for supporting said inner floor elements; b) each inner floor element comprises an edge made of a heat-conductive material which has a lower bearing surface that is substantially horizontal and oriented downwards, intended to be placed on said upper bearing surface of said profile member and a heat-conductive layer which extends substantially over the entire extent of said inner floor element; c) when said inner floor element is placed on said profile member for the purpose of the fastening thereof, said lower bearing surface of said inner floor element and said upper bearing surface of said elongate structural element are connected to one another by means of one or more contact surfaces; d) said elongate structural element also comprises a heating and/or cooling unit, which is connected to said profile member by means of one or more contact surfaces ensuring good thermal conductivity between said heating and/or cooling unit and said profile member and which is arranged with respect to said profile member in such a way that the thermal fluxes generated by said heating and/or cooling unit are transmitted by said elongate structural element to heat or to cool the ambient air present inside said vehicle; e) said heat-conductive layer belongs to the same part as said edge or is connected to the latter by means of one or more contact surfaces ensuring good thermal conductivity between said edge and said conductive layer; f) said contact surface or surfaces ensure good thermal conductivity between said inner floor element and said profile member.