This invention relates to an oxide superconducting wire comprising oxide superconducting filaments, a high-density ceramic layer uniformly surrounding each of the filaments, and a silver sheath that directly covers the ceramic layer. The ceramic layer becomes non-superconducting when the filaments are cooled to an operating temperature of oxide superconductors. The oxide superconductors can be isolated by the ceramic that acts as a highly resistive material or an insulator. A high normal resistance is achieved, and thereby AC loss is reduced remarkably.