To uniformly promote the entering into solid solution of carbides in the course of heating and holding even in the case of heating at extremely low temp. for extremely short time and to obtain a high carbon steel having stable and excellent hardenability by specifying the average grain size and grain size distribution of carbides in a high carbon steel of specific C content, respectively.

In a high carbon steel which has a composition containing, by weight, ≥0.2%, preferably ≤ about 2.0%, of C and preferably containing ≤ about 2% Mn, ≤about 2% Si, ≤ about 0.03% P, ≤ about 0.03% S, ≤ about 0.08% Al, ≤ about 0.01% N, etc., the average grain size of carbides in its steel structure is regulated to ≤0.9 μm and carbides having ≤1.1 μm grain size comprise ≥80%, and further, the maximum grain size of carbides is regulated to 1.4 μm. This steel structure can be obtained by hot-rolling a slab of prescribed composition at ≤ about 1200°C, finishing hot rolling at a temp. not lower than the Ar3 point, coiling the resultant rolled steel at ≤ about 650°C, and performing annealing at ≤ about Ac3-30°C. By this method, the carbides can be allowed to enter into solid solution rapidly and uniformly by means of hardening at ≤750°C for about 10 sec, and desired hardness can be stably obtained.