THRUST BEARING DEVICE FOR SUPERCHARGER

A thrust bearing device 40A is constituted by a turbine-side thrust collar 42 and a compressor-side thrust collar 44 that are fixed to a rotary shaft 12; and a thrust bearing (46) that is arranged between the thrust collars. The thrust bearing 46 is provided with an oil passage 48 that supplies lubricating oil r to sliding-contact surfaces formed between the thrust bearing 46 and the thrust collars 42 and 44. The outsides of the thrust collars 42 and 44 in a radial direction incline toward the thrust bearing 46 side. A gap c between the sliding-contact surfaces is narrowed as the gap goes outward in the radial direction, and establishes a basic region gap (c1) > an outer peripheral end gap (c2). The lubricating oil outflow resistance of a radial outer region of the gap c becomes larger than that of a radial inner region. Therefore, the lubricating oil r can be kept from flowing out from a radial outer outlet.