A metal substrate for an oxide superconducting wire, which comprises a polycrystalline metal substrate with a rolled aggregate structure having a {100} plane which is parallel to the rolled surface and a <001> axis which is parallel to the rolling direction, and an oxide crystal layer comprising an oxide of the polycrystalline metal and formed on a surface of the polycrystalline metal substrate, wherein at least 90% of grain boundaries in the oxide crystal layer have an inclination of 10.degree. or less, and at least 90% of the {100} plane of the oxide crystal layer make an angle of 10.degree. or less with the surface of the polycrystalline metal substrate.