Abstract: Projected portions 34 formed at the external circumferential edge of a tank 2 are made to engage with, at least, groove portions 36 formed at a brazing filler metal supplying member 23 and groove portions 39 formed at a connector 9 to hold the tank 2, the brazing filler metal supplying member 23 and the connector 9 together in a stable state prior to the brazing process. The structure provides a reliable means for supplying brazing filler metal material to be used to braze a tank not clad with a brazing filler metal layer and a connector formed through machining. In addition, it effectively prevents the member constituting the means for brazing filler metal supply from coming off.