An oxide superconductor wire including: a superconductor laminate including a tape-shaped substrate, an interlayer, an oxide superconductor layer, and a protection layer which are formed on the substrate; a metal stabilization layer covering the periphery of the superconductor laminate; a first electrically conductive joint material arranged between the superconductor laminate and the metal stabilization layer; and a sealing member formed from a metal foil, connected to a terminal of the superconductor laminate, and extending in the longitudinal direction of the superconductor laminate, wherein the metal stabilization layer includes an extension part formed so as to cover the periphery of the sealing member, and wherein the first electrically conductive joint material includes an extension part arranged between the extension part of the metal stabilization layer and the sealing member and formed so as to cover the periphery of the sealing member.