Austenite in modified-13%Cr (generic classification of 13Cr-5Ni-2Mo 13Cr-4Ni-1Mo and other similar chemistries) has already been mentioned that corrosion-resistance properties are almost the same in a likely range of austenite volume ratio in modified-13Cr. Now that higher grades of martensite-based stainless steel have been widely used as OCTG materials this paper is concerned with austenite in higher Cr-added martensite-based OCTG materials of martensite-based 15%Cr-added stainless steel for OCTG application (15Cr-6Ni-2Mo-1Cu: UNS No.S42625) and martensite+ferrite-based 17%Cr-added stainless steel for OCTG application (17Cr-4Ni-2.5Mo-1Cu).Electrochemical analyses were carried out to compare corrosion resistance properties among 15%Cr-added and?also among 17%Cr-added stainless steels with likely ranges of austenite which were prepared as reversely-transformed austenite during laboratory-tempering at around slightly higher temperature than ferrite/austenite transformation temperature.The results showed that 15%Cr-added stainless steel has almost the same tendency regardless of austenite volume ratio in terms of rest potentials pitting potentials and repassivation potentials and 17%Cr-added stainless steels as well. It indicates that austenite in 15%Cr-based and 17%Cr-based stainless steels has little impacts on each corrosion resistance. The paper will also mention the correlation of some mechanical properties to austenite volume ratio.