PROBLEM TO BE SOLVED: To prevent feces leakage in a sitting posture.SOLUTION: Three-dimensional gather BS comprises: a gather sheet 15 including a root part 15a to be fixed to the disposable diaper, a bellows-like projection part 15b that projects from the root part 15a and is formed by folding it back a plurality of times in the width direction in the front side of the disposable diaper, longitudinal folding parts 17 that are formed by fixing front/back ends of the projection part 15b in folded states respectively, an intermediate fixing part 18 that is formed by fixing at least tip end that is in the back side of the front end at the projection part 15b and in the front side of the anus position, to the surface of the disposable diaper, and stretchable free parts 19 that are located at the projection part 15b between the longitudinal folding parts 17 and the intermediate fixing part 18 and gather elastic members 16 that are fixed to the at least tip ends of the free parts 19, while being stretched in the longitudinal direction.
