The present invention provides a disposable pants-type diaper including on a crotch region thereof a separator adapted to prevent body wastes from coming in contact with the wearers skin. A basic structure 10a has the crotch region 6, which is provided with a folded sheet piece 61 attached thereto so as to form the separator 20. The folded sheet piece 61 is obtained by folding back the sheet piece 20a along a first transverse center line thereof to define a first half 71 and a second half 72 placed upon each other and bonding end edges of these two halves to each other at responsive middles of these end edges in a transverse direction. With the first transverse center line brought close to a second transverse center line, the folded sheet piece 61 is placed upon the crotch region 6 and the lateral edges of the first half 71 are bonded to the crotch region 6 while a region of the first half 71 defined by the lateral edges is kept to be spaced from the crotch region 6. Then, the basic structure 10a is folded back along the second transverse center line and the inner surface of the basic structure 10a is bonded to the outer surface of the lateral edges of the second half 72 while a region of the second half 72 defined between the lateral edges is kept to be spaced from the crotch region 6. Of the basic structure 10a folded back in this manner, the front and rear waist regions 7, 8 are bonded along the lateral edges 7a, 8a to make the basic structure 10a in a pants-shape.
