Provided is a pants-type disposable diaper (1) including: an absorbent body (10) which is folded in two in a prescribed position in the longitudinal direction and is disposed with the longitudinal direction aligned in the vertical direction a ventral side waist portion (31) overlaid on a non-skin side surface of an end portion on one side in the longitudinal direction of the absorbent body (10) and a dorsal side waist portion (41) overlaid on the non-skin side surface of an end portion on the other side in the longitudinal direction of the absorbent body (10). The absorbent body (10) includes an absorbent core (11c) which absorbs liquid and sheet-like flap portions (10f) which protrude further out in the lateral direction than the absorbent core (11c). The flap portions (10f) include on both the one side and the other side Z-shaped folded parts (10fZ 10fZ) secured while folded in a Z-shape in the lateral direction. The Z-shaped folded parts (10fZ 10fZ) are secured respectively to parts of the ventral side waist portion (31) and the dorsal side waist portion (41) located to the outside of the absorbent core (11c) in the lateral direction.
