LASER WELDING METHOD

PROBLEM TO BE SOLVED: To provide a laser welding method which can suppress the warpage of the central section of a lid, and at the same time, can reduce the replacement frequency of a pressing member. SOLUTION: Not only the external edge of the lid 2 but also the internal side, i.e., both of the external side and the internal side on which the laser welding is performed are pressed by the pressing member 3. In concrete, the pressing member 3 for which an end pressing section 3a, a center pressing section 3b and a combining member 3c are integrated is used. When the lid 2 is pressed by the pressing member 3, the lid 2 does not warp with a bonding protruding section 1d as a fulcrum when the laser welding is performed. Therefore, the swelling or the like of the central position of the lid 2 can be prevented from occurring. COPYRIGHT: (C)2008,JPO&INPIT