It is an object of the invention to provide an absorbent article that is resistant to twisting and flattening, and that is superior in terms of fluid absorption rate, fluid diffusibility, absorbed fluid retention volume and fluid retention. The absorbent article comprises a top sheet on the skin contact side, a back sheet on the non-skin contact side, and an absorbent body situated between the two sheets, wherein the absorbent body comprises a bulky absorbent sheet, and the bulky absorbent sheet comprises heat-expanding particles that are dispersed in the bulky absorbent sheet and have been expanded by heat.