A bearing structure of a turbo charger is provided. The turbo charger includes a semi-float bearing, a rotary shaft. The semi-float bearing is cylindrical and mounted in the bearing housing. The rotary shaft passes through the semi-float bearing and is supported rotatably by the semi-float bearing. The bearing structure includes a slinger wall and a projecting portion. The slinger wall is provided on the rotary shaft so that it is opposed to an end face in the axial direction of the semi-float bearing. The projecting portion projects from at least one of the slinger wall or the end face to the other. The projecting portion is provided in an annular shape along the circumferential direction of the semi-float bearing. The projecting portion includes a cutout portion that links the inner circumferential face side of the semi-float bearing with the outer circumferential face side thereof.