Research was conducted to investigate the sliding wear of Y-free and Y-containing 304 stainless steel in 0.1 mol/1 H2SO4 solution. By the sliding wear test and worn surface analysis (SEM), the authors demonstrated that yttrium considerably improved the resistance of the stainless steel. In order to clarify the mechanism responsible for the improved corrosive wear resistance, yttrium effects on microhardness and polarization behavior of 304 steel were investigated. In particular, the damage and self-healing of passive film was determined using a scratch tester in combination with an electrochemical measurement system. Micro-scratch and micro-indentation tests were also performed with monitoring changes in the electrical contact resistance to evaluate the failure resistance of passive films respectively on Y-free and Y-containing 304 steel specimens. It was demonstrated that yttrium did not significantly influence the mechanical properties of the steel. However, a remarkable improvement in the polarization behavior of 304 steel with the formation of a stronger passive film was observed when a small amount of yttrium was alloyed into the steel. The mechanism responsible for the beneficial effect of yttrium on corrosive wear resistance of the stainless steel is discussed.