Provided is a method of manufacturing an absorbent article including an absorbent main body, a pair of first side flaps provided at one end section of the absorbent main body in a longitudinal direction and a pair of second side flaps provided at the other end section of the absorbent main body in the longitudinal direction. The manufacturing method includes (1) forming a pair of side flap-folded sections by folding a continuous sheet such that end sections in a width direction of the continuous sheet are folded inwardly in the width direction, respectively, while the continuous sheet that is a base material of the first and second side flaps is being transported in a continuous direction of the continuous sheet, (2) producing a flap segment by segmenting the continuous sheet at a predetermined pitch in the continuous direction, (3) joining the flap segment to a continuous body of absorbent main bodies in an overlapped manner, while the continuous body of absorbent main bodies is being transported in a transport direction corresponding to a continuous direction of the continuous body, and (4) dividing the flap segment into a section having the pair of first side flaps and a section having the pair of second side flaps by segmenting the continuous body of absorbent main bodies.
