To provide a welding method for members where a friction welding with a comparatively low heat input is used and the appearance of the rear side of a welded plate material after welded is easily and certainly improved.

A protruding part 3 for welding is formed at the welded part of the surface 1a of a plate-shaped base material 1, a member 2 to be welded is placed in a butting manner on the upper face 3a of the protruding part 3, and a friction welding is carried out. Since the rear side 1b of the welded plate material 1 is scarcely affected by the friction heat given at the welding, a recess on the rear side 1b or a deformation due to heat at the welded part is prevented or minimized.