The present invention aims to provide a pull-on disposable wearing article having leg-openings of sufficient size and assuring that respective peripheries of the leg-openings reliably cover the wearer's buttocks without apprehension that the peripheries of the leg-openings might collapse inward. A crotch panel (13) at least includes an absorbent structure (11) located on a skin-facing surface of a crotch region (16) and a pair of elastic side flaps (53) extending outward in a transverse direction (X) from both side edges of the absorbent structure (11). The elastic side flaps (53) have inelastic regions (57A) defined on the outer sides in the transverse direction (X) of both side edges of the absorbent structure (11) and elastic regions (57B) defined on the outer sides in the transverse direction (X) of the respective inelastic regions (57A). The crotch panel (13) has a dimension (W2) in the transverse direction (X) corresponding to about 55 to about 70% of a dimension (W1) in the transverse direction (X) of the front and rear waist regions (14, 15).
