PURPOSE: To efficiently cool/heat liquid and air by circulating them by vertically forming a projection or recessed part having a flat part over a full height on the side surface of a vessel made of metal, etc., and closely fixing the mechanism of a Peltier element.

CONSTITUTION: A vessel 1 is cylindrically formed and on its outer side surface, a flat protruding part 2 having the width of a pair of Peltier elements is formed over the full length of the vessel in the state of facing at 180°. On the outer side surface of the protruding part 2, a Peltier element mechanism 2 is closely fixed on the vessel 1. Further, a heat absorbing/radiating instrument 5 having a heat absorbing/radiating fin 4 is closely fixed on the outer surface of the Peltier element mechanism 3 and heat is exchanged with the outside by pumping the heat of liquid or gas in an internal part 6 of the vessel 1. When filling the vessel 1 with water and cooling it, first of all, the contact part of the vessel 1 is cooled by the Peltier mechanism 3, the vessel 1 is cooled with spreading on its surface by successive heat conduction and since the inside water is simultaneously cooled as well, the spread of heat conduction is not enlarged so much.