PURPOSE: To manufacture an oxide high temperature superconducting wire rod more improving critical current density.

CONSTITUTION: Inside a metal sheath is charged with material powder of a Bi oxide superconductor, and plasticizing work is applied thereto, so as to obtain a tape wire. Heat treatment is applied to the obtained tape wire at a temperature in a degree of not forming a sintered body of the oxide superconductor. Thereafter to the wire applying the heat treatment, a sintering process is applied. By the heat treatment before the sintering process, critical current density higher than in the case of not applying this heat treatment can be brought in the finally obtained superconducting wire.