A half thrust bearing having a semi-annular shape includes a sliding surface for receiving an axial force of a crankshaft of an internal combustion engine, and a rear surface on an opposite side of the sliding surface, and defines a reference plane on the rear surface side that is perpendicular to an axial direction. The sliding surface includes a flat surface portion near a circumferentially central portion and in parallel with the reference plane, and inclined surface portions on both sides of the flat surface portion in a circumferential direction. At any radial positions of the half thrust bearing, an axial distance between the reference plane and the sliding surface is maximum at the flat surface portion, and is reduced in the inclined surface portions toward both circumferential end portions of the half thrust bearing.