In a wider flow path 4a surrounded with a shaft 3, a thrust plate 6 and an inner circumferential corner portion 1c of a bearing sleeve 1 in a small clearance 4 between a lower side radial bearing section 13 and an upper surface thrust bearing section 14, chamfering is performed at the inner circumferential corner portion 1c of the bearing sleeve 1, wherein a width of the wider flow path 4a in the radial direction in rotation is formed so as to be wider than a width of a communication hole 16 located below the wider flow path 4a in the radial direction in rotation to thereby render a flow of a lubricating fluid 5 flowing into the wider flow path 4a from the communication hole 16 smooth.