In order to investigate friction and wear characteristics of the thermal diffused Sn plated stainless steel in vacuum, ring on disk tests were performed. In case of the tests in vacuum the friction coefficient at high temperature was slightly smaller than that at room temperature, while the specific wear rate at high temperature was greater than that at room temperature. In case of the tests in vacuum the friction behavior was stable and the wear was small after the wear depth was equivalent to the thickness of the modified layer. On the contrary both the friction coefficient and the wear were increased with increasing sliding distance and the wear exceeded the modified layer.