PROBLEM TO BE SOLVED: To allow a fastening force of a girth part to be easily adjusted into a targeted fastening force.SOLUTION: In an underpants type disposable diaper, a girth part of an exterior body 20 has a waist edge part elastic member 24 which is fitted in a width direction in the state that it is expanded at a first expansion rate, and an inner layer 20C and an outer layer 20D facing an inside and an outside of the waist edge part elastic member 24. The waist edge part elastic member 24 of a front body section F decreases in shrinkage force which is exhibited at the same expansion rate as a maximum value of an experiential expansion rate is updated. The front body section F of the exterior body 20 has: a non-fixed adjustment area 30 where the waist edge part elastic member 24 is fixed to neither the outer layer 20D nor the inner layer 20C and a fixed area 31 which is located on both sides in the width direction of the adjustment area 30 and in which the waist edge part elastic member 24 is fixed to at least either the outer layer 20D or the inner layer 20C. The waist edge part elastic member 24 in the adjustment area 30 is elastic by an expansion rate higher than a first expansion rate.COPYRIGHT: (C)2016,JPO&INPIT【課題】胴周り部の締め付け力を、容易に目的の締め付け力に調節できるようにする。【解決手段】上記課題は、外装体20の胴周り部に、幅方向に第1の伸長率で伸長された状態で取り付けられたウエスト縁部弾性部材24と、このウエスト縁部弾性部材24の内側及び外側にそれぞれ面する内側層20C及び外側層20Dとを有している、パンツタイプ使い捨ておむつにおいて、前身頃Fのウエスト縁部弾性部材24は、経験伸長率の最大値が更新されるとそれに応じて同じ伸長率で発揮される収縮力が低下するものであり、外装体20の前身頃Fは、ウエスト縁部弾性部材24が外側層20D及び内側層20Cに固定されない非固定の調節領域30と、この調節領域30の幅方向両側に位置し、ウエスト縁部弾性部材24が外側層20D及び内側層20Cの少なくとも一方に固定された固定領域31とを有しており、調節領域30におけるウエスト縁部弾性部材24が、第1の伸長率よりも高い伸長率に伸長可能とされていることにより解決される。【選択図】図9
