Abstract: The invention concerns a method of constructing a heat exchanger as well as a heat exchanger constructed in accordance with said method. The method comprises piling of essentially similar corrugated thermal transmission plates to cover each other and connecting the spaces between the plates from their edges to inlet and outlet conduits for the mediums participating in thermal transmission so that through every second space between the plates is passed a flow of heat giving medium and through every second space between the plates a flow of heat receiving medium. Essential to the present invention is that the pressure losses of flows and the thermal transmission coefficient of the exchanger are established by piling the thermal transmission plates one over another so that the grooves in different plates are placed at a selected angle with each other.