A supercharger includes a housing (40) and a turbine shaft supported by the center hole (43) within the housing (40) through rolling bearings (10A,10B). A cooling water jacket (26) within the housing (40) is provided within the main body portion (40B) of the housing (40). The rolling bearings (10A,10B) are supplied with lubricant by a tank portion (35) formed within the housing (40) for reserving the lubricant and a wick member (36) provided between the tank portion (35) and the center hole (43). The wick member (36) includes a core portion (37) configured by a fiber portion (37a) and gaps (37b). The lubricant is supplied by the capillary action of the gaps (37B). The porosity of the gap (37B) is set to be 45.5 % or more and less than 80 %.
