A disposable pant type undergarment includes a ventral member, a dorsal member and a crotch member that bridges the ventral member and the dorsal member. A crotch edge of the ventral member and the dorsal member each includes right and left edge lines, right and left tilted lines and a central line. The edge lines are approximately parallel in a waist-around direction. Nearer the central line, a distance between a waist opening of the undergarment and the tilted lines of the ventral member is shorter, and a distance between the waist opening and the tilted lines of the dorsal member is longer. Tilted portions of a leg-surrounding elastic body extend in a leaving direction from the crotch edge of the ventral member and extend into an area overlapped with the ventral member and the crotch member.