PURPOSE: To prevent the transfer of heat from an external source into the title device through a Peltier element when the excitation of the Peltier element is stopped, in the cooling device, in which cooling is effected by Peltier effect.

CONSTITUTION: A heat exchanger 3 for a Peltier element, which incorporates a liquid channel 2, is arranged at the cooling side of the Peltier element 1 so as to be contacted while the liquid channel of the heat exchanger 3 for the element is interposed in the forced circulation passage 5 of liquid, which is provided with gas in at least a part of it. The device is constituted so that the gas flows into the liquid channel 2 and retained therein when the forced circulation of the liquid is stopped in accordance with the interruption of excitation.