PURPOSE: To obtain a heat exchanger serviceable for both A.C. and D.C., which is easy to manufacture at low cost, by laminating a heat exchanger elements to be constituted by combining a pair of divided elements so that their corrugated sheets are overlapped one upon another.

CONSTITUTION: As for each of a pair of divided elements 1, a heat exchanger element 7 is formed by shifting mutually corrugated plates 3, 3 by a half wavelength, overlapping and being combined under contact state by making a pointing directions of mountainlike parts coincide with each other. Under this condition, each of ventilating parts 4, 4 of the dividing elements 1, 1 is connected in an inclined state with each other, through which a connecting duct 8 is formed. The heat exchanger elements 7 are laminated in a plurality of steps in a mutually touching state by making the pointing directions of the crest parts of the overlapped corrugated plate 3 coincide, through which a second air duct 9 is formed by connecting ducts 8 with each other and heat exchange is carried out between the air in the first air duct 5 and the air in the second air duct 9.