PURPOSE: To obtain the welding method of a member to be mounted, in which no melted adhesive scatters at welding, and the structure of a welded part.

CONSTITUTION: A peripheral wall 36 is disposed in upright on the periphery of the base plate 32 of a catch 30. Inside the peripheral wall 36, a housing wall 40 is installed in upright under the condition that the predetermined gap 42 is held between the peripheral wall 36 and the housing wall 40. In the housing wall 40, hot melt agent 38 is housed. When the exposed surface of the hot melt agent 38 is rotated under the condition being pushed against a mounting board with a rotary jig holding the catch 30 thereon, the hot melt agent 38 is melted by means of frictional heat. Since the hot melt agent is surrounded by the peripheral wall 36, the hot melt agent 38 under molten and liquid state tending to scatter to its surroundings due to centrifugal force abuts against the peripheral wall 36 and collects in the gap 42. Thus, the molten hot melt agent 38 can be prevented from scattering. After that, the hot melt agent cools down and hardens, resulting in fusion-bonding the catch 30 to the mounting board.