Device for thermal conditioning of fluid comprising: - a fluid circulation valve, notably for a motor vehicle, comprising a body and a sealing element able to occupy different angular positions by the rotation of said element relative to said body, said body having a first, a second, a third and a fourth inlet/outlet, said valve being configured so as to permit: - in a first of said angular positions, the circulation of the fluid from the first to the second inlet/outlet, - in a second of said angular positions, the circulation of the fluid from the first to the third inlet/outlet and from the fourth to the second inlet/outlet, - in a third of said angular positions, the circulation of the fluid from the first to the fourth inlet/outlet and from the third to the second inlet/outlet, - a heat exchanger connected between said third and said fourth inlets/outlets in the region of a so-called cooled line, said first and second inlets/outlets are radial and said third and fourth inlets/outlets are axial; - said body comprises an internal cylindrical housing of circular cross section, characterized in that said sealing element comprises at least one sealing part arranged in a plane which is inclined relative to said cylindrical housing and cooperating with the lateral wall of said housing by a peripheral generatrix, so as to ensure sealed contact between the sealing element and the body in at least one angular position, said sealing element comprising a control rod which is connected to the inclined part to drive said inclined part in rotation and which is arranged in the axis of said cylindrical housing passing via the centre of said inclined part. - a fluid circulation valve, notably for a motor vehicle, comprising a body and a sealing element able to occupy different angular positions by the rotation of said element relative to said body, said body having a first, a second, a third and a fourth inlet/outlet, said valve being configured so as to permit: - in a first of said angular positions, the circulation of the fluid from the first to the second inlet/outlet, - in a second of said angular positions, the circulation of the fluid from the first to the third inlet/outlet and from the fourth to the second inlet/outlet, - in a third of said angular positions, the circulation of the fluid from the first to the fourth inlet/outlet and from the third to the second inlet/outlet, - a heat exchanger connected between said third and said fourth inlets/outlets in the region of a so-called cooled line, said first and second inlets/outlets are radial and said third and fourth inlets/outlets are axial; - said body comprises an internal cylindrical housing of circular cross section, characterized in that said sealing element comprises at least one sealing part arranged in a plane which is inclined relative to said cylindrical housing and cooperating with the lateral wall of said housing by a peripheral generatrix, so as to ensure sealed contact between the sealing element and the body in at least one angular position, said sealing element comprising a control rod which is connected to the inclined part to drive said inclined part in rotation and which is arranged in the axis of said cylindrical housing passing via the centre of said inclined part.