In a method of manufacturing an absorbent article, an absorbent article 1 is manufactured in which backsheets are in continuation, in a state in which the longitudinal direction of the absorbent article 1 corresponds to the conveyance direction MD of a continuous body 120. The method the absorbent article includes: a step of pressing the continuous body 120 in a thickness direction T of the continuous body 120 by a pair of embossing roll mechanisms 520, a step of expanding the continuous body 120 that has been pressed towards outside a widthwise direction CD of the continuous body 120 until it becomes flat, by a pair of expansion roll mechanisms 600, and a step of joining a absorber 30 with the continuous body 120 of the backsheet.