Abstract: The invention relates to a counter flow enthalpy exchanger (1) having a parallelogram-shaped central part (11), whose ends in the flow direction through the exchanger it is joined by end parts (12, 13), which become narrower in the direction from the central part (11), whereby in order to separate the flow of the heat-transfer medium in the direction from the inner space to the outer space are arranged contour identical and with respect to the flowing medium sealed vapour-permeable lamellae (10) with shaping means for generating turbulent flow, whereby every two adjacent lamellae (10) form one interplate flow channel in the central part (11) one interplate flow channel. The lamella (10) is made as a one-piece self-supporting moulding common to the central part (11) and the end parts (12, 13), whereby it does not have a reinforcing support grid.