It is a stretchable/contractible sheet (31) in which a plurality of elastic members (35) arranged between a first sheet (32) and a second sheet (33) joined by a plurality of welded portions (50). The stretchable/contractible sheet (31) includes, above a certain elastic member (35), a first welded portion (51) and a third welded portion (53). The stretchable/contractible sheet (31) also includes, below the certain elastic member (35), a second welded portion (52) and a fourth welded portion (54). the certain elastic member is attached by being sandwiched in the up-down direction between the first welded portion (51) and the second welded portion (52) and by being sandwiched in the up-down direction between the third welded portion (53) and the fourth welded portion (54). The first welded portion (51) and the third welded portion (53) having portions overlapping in the up-down direction. The position of the lower end of the first welded portion (51) is different in the up-down direction from the position of the lower end of the third welded portion (53).
