The invention provides a supercharger which is provided with a thrust bearing in an outer side of a radial bearing, and can smoothly discharge a fed lubricating oil from a bearing portion so as to reduce a resistance generated by the lubricating oil.The supercharger is provided with a thrust bearing (30) rotatably supporting a thrust force applied to a turbine shaft (12). The thrust bearing (30) is constituted by a disc-shaped thrust collar (32) rotating together with the turbine shaft, and a turbine side thrust bearing (34) and a compressor side thrust bearing (36) inhibiting a movement in an axial direction of the thrust collar. The compressor side thrust bearing (36) has an oil feed flow path (36a) feeding a lubricating oil to a surface coming into contact with a thrust collar from an inner side of a housing, an annular concave groove (36b) provided in an inner surface of a hollow through hole through which the turbine shaft passes, and an oil discharge flow path (36c) dropping down the lubricating oil reserved within the concave groove downward.