A vapor deposition metal mask substrate includes a nickel-containing metal sheet including a obverse surface and a reverse surface, which is opposite to the obverse surface. At least one of the obverse surface and the reverse surface is a target surface for placing a resist layer. The target surface has a surface roughness Sa of less than or equal to 0.019 μm. The target surface has a surface roughness Sz of less than or equal to 0.308 μm.