The provision of a disposable underwear-style diaper that is easy to put on. Each leg flap (42) of a crotch panel (14) of this disposable underwear-style diaper (10) has an outer region (91) and an inner region (92). At the lowermost end (70) of a crotch region (4), said outer region (91) and inner region (92) are each at least 10 mm wide in a width direction (X). The inner region (92) extends in a vertical direction (Y), whereas the outer region (91) extends, from the inner region (92), in the horizontal direction (X).