To provide a method for producing steel with a ultrafine ferritic structure which does not cause separation in a Charpy test while maintaining sufficient strength and toughness as steel for structural purposes, and has no reduction of shelf energy.

A steel stock containing precipitate forming elements is heated at the Ac3 point or higher. After that, the steel stock is rolled at a draft of ≤40%, or is not rolled, and is cooled to the temperature lower than the Ac3 point. Next, heating to the Ac3 point or higher and cooling to the Ac1 point or lower are repeated, respectively, for one or more times. Finally, the steel stock is heated to the Ac3 point or higher and rolled at the Ar3 point or higher, and is thereafter cooled. The cooling is carried out preferably by a method of performing rapid cooling at ≥3°C/s directly after the rolling, and stopping the cooling at ≥500°C.