An expandable/contractable sheet (31), in which a plurality of elastic members (35) are positioned between a first sheet (32) and a second sheet (33) that are joined by a plurality of weld sections (50), has a first weld section (51) and a third weld section (53) on an upper side of one elastic member (35) and has a second weld section (52) and a fourth weld section (54) on a lower side of the one elastic member (35). The one elastic member (35) is attached by being clamped in a vertical direction by the first weld section (51) and the second weld section (52) and being clamped in the vertical direction by the third weld section (53) and the fourth weld section (54), the first weld section (51) and the third weld section (53) have portions that overlap in the vertical direction, and the lower edge position of the first weld section (51) and the lower edge position of the third weld section (53) are not aligned in the vertical direction.本發明的課題係在於提供具有柔軟性並且不易產生彈性構件的位置偏移之伸縮性薄片。 用以解決課題之手段為，一種伸縮性薄片，係在藉由複數個熔接部(50)所接合之第1薄片(32)與第2薄片(33)之間，配置有複數個彈性構件(35)之伸縮性薄片(31)，其特徵為，在其中一個彈性構件(35)的上側，具有第1熔接部(51)與第3熔接部(53)，在其中一個彈性構件(35)的下側，具有第2熔接部(52)與第4熔接部(54)，前述其中一個彈性構件係藉由以第1熔接部(51)與第2熔接部(52)朝上下方向挾持並且藉由第3熔接部(53)與第4熔接部(54)朝上下方向挾持進行安裝，第1熔接部(51)與第3熔接部(53)係具有在上下方向上重複的部分，第1熔接部(51)的下端位置與第3熔接部(53)的下端位置係在上下方向上偏移。
