A solid solution powder capable of manufacturing cutting tools with high hardness and high toughness by essentially greatly improving toughness of a cermet material and obtaining superior mechanical properties of the cermet material as a whole, thereby substituting a WC-Co hard metal material, a preparation method of the solid solution powder, a powder for cermet comprising the solid solution powder, a preparation method of the powder for cermet, sintered ceramics using the solid solution powder, and a cermet using the powder for cermet are provided. A solid solution powder is formed of carbide, carbonitride, or a mixture of the carbide and the carbonitride of at least two metals that include titanium and are selected from metals of IVa group, Va group and VIa group on the periodic table of the elements, wherein the solid solution powder is completely in a solid solution phase with a solid solution powder having nanograins of 100 nm or less. A preparing method of a solid solution powder comprises: a step(S1-1) of mixing nano-sized oxides of at least two metals with a carbon powder or a carbon source according to a desired composition, wherein the at least two metals include titanium and are selected from metals of IVa group, Va group and VIa group on the periodic table of the elements; and a step(S2) of reducing and carbonizing the mixed powder of the oxides and the carbon powder or the carbon source.