PURPOSE: To obtain superconducting ceramic oxide products having excellent mechanical strength, rigidity, etc., by densifying superconducting ceramic oxide under heating and pressurizing to form a dense composite of an approximate superconducting state, then regenerating the superconducting state.

CONSTITUTION: The superconducting ceramic oxide (e.g.; YBa2Cu3O6.8) is densified under heating and pressurizing to form the dense composite having the structure and compsn. approximate to the superconducting structure and superconducting compsn. The structure and compsn. approximate to the superconducting structure and superconducting compsn. of the dense composite are rearranged to the structure and compsn. associated with the superconducting state of the ceramic oxide, by which at least the outside surface of the composite is changed to the superconducting state and the dense superconducting ceramic oxide products are obtd. The more specific example of the rearranging state includes a method of diffusing the necessary atoms from the outside to the inside through the surface of the composite.