A half thrust bearing includes a slide surface which includes: at least two oil grooves extending in a radial direction; a plurality of pad surfaces located on both sides of each oil groove in a circumferential direction; and at least two first inclined surfaces each formed between the oil groove and the pad surface on a front side of the oil groove in a rotation direction of a crankshaft. A plurality of circumferential grooves are formed in succession in the radial direction on the first inclined surface. A plurality of oil drain grooves extends side by side to intersect the circumferential direction and the radial direction on the pad surface. A plurality of flat portions are formed each between the adjacent oil drain grooves. Each oil drain groove is open at a radially outer end and/or a radially inner end of the pad surface.