A bearing device includes a thrust bearing. The thrust bearing has a bearing surface in a half-split ring shape, and a plurality of oil grooves formed to cross the bearing surface from an inner circumferential side to an outer circumferential side. Further, the thrust bearing includes a first thrust bearing that is disposed on a side surface facing a side of a transmission, and a second thrust bearing that is disposed on a side surface facing an opposite side to the transmission. In the first thrust bearing, a bearing surface between the plurality of oil grooves is configured by including a taper surface formed so that a wall thickness becomes thicker toward a rotation direction of the crankshaft. Further, in the second thrust bearing, a bearing surface between the plurality of oil grooves is configured by a plane in which a wall thickness is constant.