A condenser (10) for use in a car cooling system, comprising a pair of parallel headers (13, 14), a plurality of tubular elements (11) whose opposite ends are connected to the headers (13, 14) and fins (12) provided in the air paths between adjacent tubular elements (11), each of the headers (13, 14) being made of a cylindrical pipe of aluminum and each of the tubular elements (11) being made of a flattened hollow tube of extruded aluminum, the opposite ends of the tubular elements (11) being inserted into slits (15) provided in the headers (13, 14) and soldered therein so as to be liquid-tight.