PROBLEM TO BE SOLVED: To obtain an oxygen sensor exhibiting a high oxygen sensitivity in an atmosphere from low to normal temperature in which a film of fluorescent substance having an extremely high oxygen sensitivity can be formed easily in cryogenic and normal temperature atmosphere, and to measure the pressure distribution accurately and easily at high sensitivity using the oxygen sensor in a trace oxygen low temperature atmosphere, e.g. low temperature wind tunnel or high layer atmospheric environment.
SOLUTION: A porous oxide film is formed electrochemically on in an electrolyte on the surface of a basic metal material 1 using the basic metal material 1 as an anode 4. The basic metal material 1 formed with the oxide film is then immersed, as a cathode 1, into a solution 13 of an optical pumping substance having oxygen-sensitive characteristics. Consequently, the oxygen-sensitive is adsorbed electrochemically into fine pores in the oxide film and a film of a light emitting substance having an extremely high oxygen sensitivity can be obtained without requiring any oxygen transmitting resin.