PROBLEM TO BE SOLVED: To provide an underpants type wearing article which hardly causes tearing in a transverse direction in a side seal part and enables detachment after use to be easily and smoothly performed.SOLUTION: An underpants type wearing article 1 includes an exterior body 3 forming an outer surface, and in the underpants type wearing article, a side seal part 4, a waist opening part 8, and a leg opening part 9 are formed by connecting both side edge parts of the exterior body 3 on the side of a front body F to both side edge parts of the exterior body 3 on the side of a rear body R. The side seal part 4 comprises a sealed edge part 41 in which an edge part of the exterior body in the front body 1A and an edge part of the exterior body in the rear body 1B are joined together at a continuous linear fusion part 40 extending in a longitudinal direction of the side seal part. In the fusion part 40, in a cross section orthogonal to a direction in which the side seal part extends, a distance Dw in an inward and outward direction P between both end parts 4a, 4b in a thickness direction Q and an inner end part 4c that is closest to the skin of a wearer between both of the end parts 4a, 4b is greater than a distance Dc in the inward and outward direction P between the inner end part 4c and an opposing site 4d' in an outer edge 4d of the fusion part.
