Abstract: Heat exchanger, which has a cooling body (9) that is in contact with a medium (11) to be cooled, on the one hand, and with a cooling medium (20), on the other hand, and transfers the heat of the medium to be cooled to the cooling medium, whereby the cooling body is composed of at least two materials, of which one is a better conductor of heat than the other, and the material of better thermal conductivity is essentially in contact with the medium to be cooled and dissipates the heat from the latter to the material of poorer thermal conductivity, which is essentially in contact with the cooling medium, to which for its part it transfers the heat, and the cooling body furthermore has sintered parts that form a porous sintered structure through which the cooling medium can flow, sintered parts being composed of the material of better thermal conductivity and of the material of poorer thermal conductivity, and the sintering temperature of the material of better thermal conductivity being less than or equal to the