Method of manufacturing a gasket and gasket

A while avoiding falling into any fastening insufficient if the fastening force by the fastener is low, to provide a method of manufacturing a gasket and a gasket which can improve the sealing performance. A least a metal plate 21 of the metal plate 21 to the metal plate 23 and the ring-shaped member 33 constituting the gasket 20, the metal plate 23 and the ring-shaped member 33 together constitute a stainless steel martensitic, first into at least a portion of at least a portion of the bore bead 30 and the second bore bead 34, to form a high hardness portion 35 of the higher hardness than the hardness of the stainless steel plate. .The