To provide a fitting method for an annular metal component which can prevent the generation of a flaw causing leakage when press-fitting the annular metal component 2 having a fitting cylinder 21 and a flange 22 into a prescribed attachment mating member 4, and to secure the seal performance of a metal fitting part.

When press-inserting the fitting cylinder 21 of the annular metal component 2 into the external peripheral face 4a of the attachment mating member 4 which is harder than the annular metal component, a press-insertion load is applied to the flange 22 extending from the rear end of the fitting cylinder 21 in the press-insertion direction in an inclined and deformed state that the flange 22 is made to fall down to the press-insertion direction by a jig 100.