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.