Zone-refining of iron was tried with the oxidization refining. The original material was vacuummelted iron. The atmosphere of zone-refining was the wet or dry hydrogen. The results obtained are summarized as follows:(1) Zone-refining in dry hydrogen was not effective.(2) Zone-refining in wet hydrogen was effective and the value of electrical resistivity ratio ρRT/ρ4.2°k of 123 was obtained after one pass refining.(3) Materials coated with CaO-SiO2 oxide mixture was zone-refined in wet hydrogen and the ratio ρRT/ρ4.2°k became to the value of 157, showing the highest purity in the present study.(4) From (2) and (3), it is supposed that the purification of iron is dependent upon the oxidation refining.(5) Non-metallic inclusions were included in the vacuum melted iron but removed effectively during zonerefining.(6) Zone-refined iron in wet hydrogen had very low lower yield stress of 13.2 kg/mm2 and very low amount of increment of flowstress due to work hardening of 2.5 kg/mm2 during the strain of 5 to 10 per cent.