We studied on the effect of tungsten, molybdenum and vanadium on the transformation points and mechanical properties of a few kind of Ni-Cr steel and stainless steel.Specimens were prepared in a 35k.V.A. high freqency induction furnace, remelting raw materials of carefully refined basic electric arc furnace steel. One of the above elements, W, Mo and V, was added to the molten steel, and after casting, ingot was forged and rolled to a rot of 20mm in diameter.At first, transformation points were determined by the thermal dilatation method, and then hardness, tension and impact tests on the same sample were carried out after various heat treatments.As for Ni-Cr steel, it is found that molybdenum is the most powerful in the descending effect on the Ar1 transformation, followed by tungsten, and vanadium is feeble. The effect of these elements on the tensile strength of Ni-Cr steel is difficult to appreciate in the case of tempering at the low temperatures such as 300°C after quenching, but when the tempering temperature is raised to 500-600°C, the effect becomes remarcable; that is vanadium is most affective and tungsten is rather feeble.In the case of the stainless steel, containing 18% chromium and 8% nickel, tungsten, molybdenum and vanadium act to increase the tenacity. On the stainless steel of 13% chromium type, it is found that the above three elements slightly affect on the physical properties.