The present invention addresses the issue of improving the fit of an edge section of an outer cover body around the legs. In at least one outer cover body (12F 12B) out of a ventral outer cover body (12F) and a dorsal outer cover body (12B): a section positioned on both sides in the width direction of an inner cover body (200) in the lower edge of a side edge section corresponding area corresponding to a side edge section and the front/rear direction forms an edge (Le) for a leg opening a lower side section of the side edge section corresponding area is a folded back section (12W) being folded once or folded a plurality of times in a zig zag in the front/rear direction in the side edge section the folding expands gradually from the folded back section (12W) towards the width direction center and a long narrow inclined elastic stretching/shrinking member (19) is fixed to the inner cover body (200) in a state partially or completely expanded towards the lower side in the width direction center section same being fixed in an elongated state from the folded back section (12W) along a direction further towards the side edge section lower than the folded back section (12W) in the inner cover body (200).
