A pair of longitudinal grooves 51, 51 extending in the longitudinal direction X, and a lateral groove 52 continuing on from the longitudinal front ends 51a of the longitudinal grooves 51 and extending inwardly in the lateral direction Y, are formed on the skin-facing surface 2a of a main body 5 in a front part A. Elastic parts 12 of standing gathers 10 jut outward in the lateral direction Y from an upper end part 11a of 1 wall portion 11, the inner edge 12p thereof being conjoined to the upper end part 11a, and the outer edge 12q forming a free side edge. In the front part A and a rear part C, respectively, there exist non-elasticized regions 12A, 12B of inhibited stretchability in which the elastic part 12 is joined to the main body 5, and an elasticized region 12c. The boundary 12D between the non-elasticized region 12A and the elasticized region 12C in the front part A is positioned at the same position as the longitudinal front end 52a of the lateral groove 52 in the longitudinal direction X, or to the rear side in the longitudinal direction X from the longitudinal front end 52a.
