PURPOSE: To obtain the title thin film with composition made proper after annealing by controlling the ratio of the deposition amount of a component oxide having higher vapor pressure when component oxides for an oxide super conductor are to be put to physical deposition on a substrate.

CONSTITUTION: In the objective oxide superconducting thin film production processes comprising (1) a process to physically deposit component oxides for an oxide superconductor on a substrate and (2) an annealing process for the resultant deposition layer, the following constitution is added; that is, in the above physical deposition process, the ratio of the deposition amount of a compo nent oxide with higher vapor pressure is continuously increased over the entire specified period containing the end point of the deposition process. For example, in forming a Bi-Sr-Ca-Cn-O-based superconducting thin film, the deposition of a Bi2O3 component with higher vapor pressure is continuously increased. This period and the extent of the increase are determined after practical annealing treatment is made on the resultant deposition layer formed at a uniform superconductor composition ratio over the entire film.