Thermal conditioning device for an electric vehicle comprising a coolant circuit and a heat-transfer fluid circuit, - the coolant circuit comprising at least one compressor, an external heat exchanger, a first expansion member installed between the compressor and the external heat exchanger, and two internal heat exchangers (7, 8, 9), including an evaporator and a coolant/heat-transfer fluid exchanger, - the heat-transfer fluid circuit comprising at least one first heat exchanger that can be associated with a component of an electric power chain, a first heat-transfer fluid circulation pump, a first radiator and a second radiator, - the first radiator, the external heat exchanger and the second radiator being arranged to be passed through in that order by an outside air flow, characterized in that the heat-transfer fluid circuit comprises a means for controlling the circulation of the heat-transfer fluid that can: - apply a circulation of the heat-transfer fluid between the first heat exchanger and the second radiator, and/or - apply a circulation of the heat-transfer fluid between the first heat exchanger and the first radiator, so as to heat up the outside air flow prior to it passing through the external heat exchanger, in which the heat-transfer fluid circuit comprises a first branch in which the first heat exchanger is installed, a second branch in which the second radiator is installed, and a third branch in parallel with the second branch and in which the first radiator is installed, the control means being installed at an intersection of the second branch and the third branch, the device being characterized by the control means comprising a first two-way valve capable of connecting the first branch with the third branch, and a second two-way valve capable of connecting the first branch with the second branch, and the heat-transfer fluid circuit comprising a heat exchanger arranged to transfer calories present in the heat-transfer fluid to the inside air flow sent into the interior, this exchanger being combined with the exchanger of coolant/heat-transfer fluid type to form a sub-circuit, a circulation pump being installed in said sub-circuit, and an electric heating radiator, the sub-circuit being connected to the heat-transfer fluid circuit, by being installed in parallel with said branches (15, 16, 17). - the coolant circuit comprising at least one compressor, an external heat exchanger, a first expansion member installed between the compressor and the external heat exchanger, and two internal heat exchangers (7, 8, 9), including an evaporator and a coolant/heat-transfer fluid exchanger, - the heat-transfer fluid circuit comprising at least one first heat exchanger that can be associated with a component of an electric power chain, a first heat-transfer fluid circulation pump, a first radiator and a second radiator, - the first radiator, the external heat exchanger and the second radiator being arranged to be passed through in that order by an outside air flow, - apply a circulation of the heat-transfer fluid between the first heat exchanger and the second radiator, and/or - apply a circulation of the heat-transfer fluid between the first heat exchanger and the first radiator, so as to heat up the outside air flow prior to it passing through the external heat exchanger, in which the heat-transfer fluid circuit comprises a first branch in which the first heat exchanger is installed, a second branch in which the second radiator is installed, and a third branch in parallel with the second branch and in which the first radiator is installed, the control means being installed at an intersection of the second branch and the third branch,