In order to ensure that a braising material applied onto the surface of a header pipe does not enter communicating passages for coolant intake/outlet at a connecting block during the furnace braising process implemented to weld the connecting block utilized to connect a liquid tank to the header pipe, pipe-like projections are formed at the pair of communicating passages for coolant intake/outlet formed at the connecting block for liquid tank connection on the side where the header pipe is connected and the pipe-like projections inserted at holes of the header pipe clad with a braising material are welded to a condenser to constitute an integrated part thereof.