A bush is provided at its sliding surface with oil-supply groove portions. An
area
ratio of the oil-supply groove portions to the sliding surface of the journal shaft
is set to 30 to 90%. A length L1 between the oil-supply groove portions
in a circumferential direction and an inner diameter D of the bearing satisfy L1D/36.
Even in a bearing device in which the journal shaft and the bush mutually rotate
in a predetermined angle range or in which the journal shaft and the bush relatively
and continuously rotate, the present invention can effectively be used while maintaining
the existing sizes of the journal shaft and the bush, and it is possible to prevent
partial break of oil film or shortage of oil film.