To manufacture a high strength steel material in which fine crystal grains are produced even by simple heat treatment as well as a residual austenite structure is produced so as to realize not only high strength but high ductility, high toughness, resistance against brittle cracking, wear resistance, fatigue resistance and superior surface treatment property which are required for various usage in accordance with the usage such as cars, containers, tanks, buildings, ships, civil engineering, rails, electronic appliances, steel pipes and the like where a steel material is generally used.

The composition is controlled to contain 0.05 to 1.5% C, ≤10.0% Mn, ≤3.0% Si, ≤3.0% Al, ≤1.0% Ni, and ≤5% Mo, and the material is heat treated at a temperature where the austenite phase is present by ≥70% by volume. Then, the material is cooled to control the grain size of the ferrite phase in the metal structure to ≤3.0 μm and to allow the austenite phase to remain. In order to obtain more significant effect of making a fine structure, the material is treated under predetermined conditions of thermal hysteresis including heating temperature/time, heating/cooling rate or the like as well as times of heat treatment, distortion added during heat treatment, or the like.

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