A device for supporting and connecting electronic circuit cards, including a metal electronic circuit card guide which has grooves, one for each electronic circuit card, each groove being configured to guide an electronic circuit card in a direction of insertion towards a connector associated with it, solid walls for linking the grooves, slots which pass through at least one wall of the electronic circuit card guide, are separated by fins and grouped to form at least one heat exchange area and are arranged and designed so as to distribute the first air flow received from below the electronic circuit card guide in at least a second air flow above the electronic circuit card guide and in contact with the electronic circuit cards.