For the purpose of investigating the effect of austenitizing temperatures on the mechanical properties of 0.23%C-13.6%Cr martensitic stainless steel, tensile properties, hardness, impact value and carbide extraction were examined after changing the austenitizing temperatures and tempering temperatures. The results obtained are summerized as follows. The carbide laminations formed from hot rolling before austenitization could not be eliminated after austenitizing at 950℃. With increasing austenitizing temperature, hardness increased and showed maximum value at 1050℃ and then slightly decreased. With increasing tempering temperature up to 500℃, impact value and elongation appeard to be decreased but hardness showed nearly unchanged at austenitizing temperature of 1150℃ due to the fine M_7C₃carbides precipitation. The abrupt increase in impact value, hardness and elongation above the tempering temperature of 500℃ appeared to change in carbide structure from fine M_7C₃to coarse M_(23)C_6.