A metal wiring layer can be formed within a recess of a substrate while suppressing the metal wiring layer from being formed at the outside of the recess. A metal wiring layer forming method includes forming a catalyst layer 5 formed of Pd on a tungsten layer W on a bottom surface 3a of the recess 3 of the substrate 2 without forming the catalyst layer 5 on a surface 3b of an insulating layer of the recess 3; and forming a Ni-based metal wiring layer 7 on the catalyst layer 5 of the recess 3.