A half thrust bearing includes a sliding surface for receiving an axial force of a crankshaft of an engine, and a rear surface on an opposite side thereto. The sliding surface includes a flat surface portion near a circumferentially central portion, and two inclined flat surface portions on both circumferential sides of the flat surface portion. The axial distance between the rear surface and the sliding surface is maximum at the flat surface portion. At any radial positions, the axial distance in each inclined flat surface portion is maximum on a circumferentially central portion side and is reduced toward a circumferential end portion of the half thrust bearing. Each inclined flat surface portion is arranged to form one constant thickness portion extending linearly from a radially inner end to a radially outer end at a circumferential angle of 45°.