Each side wall part on a main body part includes a strip-like pouch part and an elastic member. The pouch part includes a first strip part extending in the longitudinal direction, and a second strip part disposed between the first strip part and the main body part and having both its edges along the longitudinal direction connecting to both edges of the first strip part. The elastic member is bonded to the first strip part linearly in the longitudinal direction. A standing part is formed in the pouch part by contraction of the elastic member. In each end part of the pouch part, a state where the pouch part overlaps with the main body part is maintained. Therefore, the height of the standing part changes gradually in a boundary part between the end part and the central part, which allows the standing part to fit against the wearers skin.
