A method for producing a disposable underwear-type diaper characterized by comprising: a first step of arranging sheet-like fasteners folded in two, on one main surface of a belt-like first continuous body having a pair of side edges (12s, 12t), at intervals along the pair of side edges (12s, 12t) of the first continuous body, so that a main surface of each fasteners is in contact with the one main surface, that both ends (23, 25) of the fasteners are disposed on the outside of the one main surface of the first continuous body when viewed from a direction of a normal to the one main surface and that a pair of the fasteners face each other in a direction in which the side edges (12s, 12t) of the first continuous body face each other; a second step of forming a composite continuous body by laying a belt-like second continuous body over another main surface of the first continuous body in a state where one ends, on the first continuous body side, of the both ends (23, 25) of the fasteners are bent so as to be laid over the other main surface of the first continuous body so that the first continuous body and the second continuous body are bonded together and that the one ends of the fasteners are fixed by bonding the one ends of the fasteners to at least one of the first continuous body and the second continuous body; a third step of cutting the composite continuous body to thereby form an individual piece divided by an imaginary line in two parts of a first region including the pair of fasteners facing each other and a second region not including the fasteners; and a fourth step of folding the individual piece in two along the imaginary line, so that the first region and the second region are laid one over the other, bending other ends of the fasteners so as to be laid over the second region, and then, fixing the other ends to the second region. a first step of arranging sheet-like fasteners folded in two, on one main surface of a belt-like first continuous body having a pair of side edges (12s, 12t), at intervals along the pair of side edges (12s, 12t) of the first continuous body, so that a main surface of each fasteners is in contact with the one main surface, that both ends (23, 25) of the fasteners are disposed on the outside of the one main surface of the first continuous body when viewed from a direction of a normal to the one main surface and that a pair of the fasteners face each other in a direction in which the side edges (12s, 12t) of the first continuous body face each other; a second step of forming a composite continuous body by laying a belt-like second continuous body over another main surface of the first continuous body in a state where one ends, on the first continuous body side, of the both ends (23, 25) of the fasteners are bent so as to be laid over the other main surface of the first continuous body so that the first continuous body and the second continuous body are bonded together and that the one ends of the fasteners are fixed by bonding the one ends of the fasteners to at least one of the first continuous body and the second continuous body; a third step of cutting the composite continuous body to thereby form an individual piece divided by an imaginary line in two parts of a first region including the pair of fasteners facing each other and a second region not including the fasteners; and a fourth step of folding the individual piece in two along the imaginary line, so that the first region and the second region are laid one over the other, bending other ends of the fasteners so as to be laid over the second region, and then, fixing the other ends to the second region.