This work was to investigate suitable tool steels for hardening using laser beam, and was studied on carbon tool steels and alloyed tool steels such as STC3 steel, STS3 steel, STD11 steel and SKH51 steel. The surface hardness of HV700-1000 and the hardening depth of 2-2.5㎜ were obtained on STC3 steel and STS3 steel, and HV800-1000 was obtained on SKH51 steel. but STDll steel was not enough. Except STD11 steel, all steels used in this study can be hardened by laser quenching or laser rapid melting.