Disclosed is a bearing device in which an Al-Sn-Si alloy sliding bearing has improved abrasion resistance against a hard steel shaft. Said bearing device comprises a combination of: a steel shaft, at least the surface of which has a hardness of 500 HV or greater; and a sliding bearing which uses an aluminum alloy containing between 2% and 10% silicon and between 10% and 18% tin by mass, with the remainder comprising aluminum and unavoidable impurities. The structure of said aluminum alloy is characterized in that the volume percentage of the tin phase is at least 50% of the volume percentage of silicon particles (the mean diameter of which is between 4 and 10 µm) and the hardness of the aluminum alloy is 45 HV or greater.
