PROBLEM TO BE SOLVED: To provide a disposable diaper having excellent breathability and capable of preventing breakage of a waist elastic sheet arranged on the back side. SOLUTION: An end flap portion and a side flap portion are formed in front of and behind the absorber and on both sides in the width direction, and a longitudinal direction is formed in the width direction between a top sheet and an exterior sheet forming the end flap portion on the back side. A rectangular waist elastic sheet is provided, and the elastic sheet includes a first waist sheet which is arranged on the anti-body side by folding the waist sheet made of non-woven fabric inward and a second waist sheet which is arranged on the body side. It is formed of an elongated elastic member that is fixed between both waist sheets and extends along the width direction, and in a plan view, the first and second openings formed in both waist sheets are separated from each other, and between them. An elastic member is provided so that the dorsal portion of the telescopic sheet in the front-rear direction extends to the vicinity of the dorsal portion of the dorsal end flap portion, and the ventral portion of the telescopic sheet in the front-rear direction is the dorsal portion of the absorber. It was extended so that it overlapped with. [Selection diagram] Fig. 4【課題】通気性に優れ、背側に配置されたウエスト伸縮シートの破断を防止することができる使い捨ておむつを提供する。【解決手段】吸収体の前後、および幅方向両側にエンドフラップ部、サイドフラップ部を形成し、背側のエンドフラップ部を形成するトップシートと外装シートの間に、幅方向に長手方向を沿わせた矩形状のウエスト伸縮シートを設け、伸縮シートは、不織布からなるウエストシートを内側に折畳んで反身体側に配置される第１ウエストシートと身体側に配置される第２ウエストシートと、両ウエストシート間に固定された幅方向に沿って伸長状態にある細長状の弾性部材で形成され、平面視において、両ウエストシートに形成された第１、２開口部を離間させ、かつその間に弾性部材を設け、伸縮シートの前後方向の背側部を、背側のエンドフラップ部の背側部の近傍まで延在させ、伸縮シートの前後方向の腹側部を、吸収体の背側部に重なるように延在させた。【選択図】図４
