A wear resisting steel was developed in the expectation that it may supersede high phosphorus gray cast iron for improving the strength of sliding elements of a marine diesel engine. In order to investigate the influence of the surface hardness and the surface modification treatment on the scuffing capacity of the wear resisting steel, the two cylinder test was carried out under oil lubrication. The test rollers had two kinds of hardnesses; one was 860 HV for bearings, and the other was 370 HV for sliding materials of cylinders. The electroless Ni-P alloy plating and sulfurizing treatments were employed. The scuffing capacity of the wear resisting steel was larger than that of the high chromium bearing steel SUJ 2. The scuffing capacity of the harder wear resisting steel was smaller than that of the softer one. The electroless Ni-P plating treatment slightly increased the scuffing capacity, while the sulfurizing treatment had no effect on the scuffing capacity of the wear resisting steel.