Three kinds of sintered SUS444 stainless steels (P/M stainless steels) whose porosity ratios were 6.9, 9.1 and 13.3 were used in this experiment, and their pitting corrosion behaviors in MgC1₂ solution were investigated by means of electrochemical measurement and SEM observation compared with normal type SUS444 stainless steel (I/M stainless steel) produced by conventional method. The pitting corrosion resistance of P/M stainless steel decreased with the increasing porosity ratio, and it was lower compared with the I/M stainless steel. The potential of pitting corrosion decreased with an increase in porosity, and the pitting corrosion rate increased as the anodic potential and the porosity ratio increased.