The Co-Cr-Mo alloy is widely applied as a biocompatible metal, because it shows excellent strength and corrosion resistance. Especially, cobalt-chromium alloy of various types has been practically used as an alloy for dental casting. By increasing the N concentration of this alloy, the mechanical properties were improved. In addition, detailed examination also seems to be necessary on the characteristics as the concentration of Cr increases. In this study, mechanical properties and corrosion resistance were considered using a tensile test and an elution test in 1％ lactic acid when N and Cr concentrations of the Co-Cr-Mo alloy were changed. As a result, the ductility was rapidly improved in 0.2〜0.4 mass％ N alloy. Also, as the Cr concentration increased from 32 mass％, the strength increased but it became brittle when it exceeded 36％. Regarding the corrosion resistance, there was no effect of the concentration of N or Cr.