To provide a welding method which can increase fixing strength of two components in comparison with a conventional method.

A welding method includes: a first process of producing a first component projected with a first welding boss half body 11 on the surface and producing a second component 2 formed with a through hole 21 through which the first welding boss half body 11 can penetrate and a second welding boss half body 22 to be combined with the first welding boss half body 11 in a state where the first welding boss half body 11 penetrates the through hole 21; and a second process of forming an enlarged part enlarged along the surface of the second component 2 by welding the first and second welding boss half bodies 11, 22 projecting from the surface of the second component 2.