PROBLEM TO BE SOLVED: To provide a method for producing an oxygen absorber which uses as a main oxygen-absorbing agent iron powder capable of absorbing oxygen in a large amount and scarcely generating hydrogen gas, while a conventional oxygen absorber has a weak oxygen adhering force to the surface of iron powder in conventional technology, because the particle sizes of the iron powder and a metal halide are simply adjusted, and while the oxygen-absorbing force of a conventional oxygen absorber prepared by adding a mechanical force is affected, because strains are generated in the particles. SOLUTION: This oxygen absorber can be obtained by mixing reduced iron powder with a metal halide and then thermally treating the mixture in a reducing atmosphere, by immersing the reduced iron powder in a organic solvent containing a metal halide, or by immersing the reduced iron powder in the organic solvent containing the metal halide and then thermally treating the mixture in the reducing atmosphere. Thereby, the physical properties of the iron powder as the main agent are improved to increase the amount of absorbed oxygen and further reduce the generation of hydrogen gas.
