A heat exchange unit includes metallic heat transfer members combined with each other. Each heat transfer member has a heat transfer face having opposite surfaces with which first and second heat exchange fluids come into contact, respectively. Welded-together flat portions of the heat transfer members are inserted into a fitting hole of an end plate. The fitting hole substantially coincides with an end shape of the combined heat transfer members and is sized to slidably receive welded-together flat portions such that the end plate and the received, welded-together flat portions contact each other. After insertion, the heat transfer members are welded to the end plate along the fitting hole so that, at the welded region, the heat transfer members and the end plate form an integral construction.