A disposable pant type undergarment (20, 40), comprising: a ventral member; a dorsal member; a crotch member that bridges the ventral member and the dorsal member bonded at center portions of the ventral member and the dorsal member; a waist opening surrounded by the ventral member and the dorsal member, wherein right and left side edges of the ventral member and right and left side edges of the dorsal member being bonded; right and left leg openings surrounded by the ventral member, the dorsal member and the crotch member; waist elastic bodies (103a, 103b) extended on the ventral member and the dorsal member in a waist-around direction; a first leg-surrounding elastic body (203c, 403c) extended at least on the ventral member around the right and left leg openings; and a second leg-surrounding elastic body (203d, 403d) extended at least on the dorsal member around the right and left leg openings; characterized in that a crotch edge of the ventral member comprises both edge lines, a pair of tilted lines and a center line, the both edge lines are approximately parallel in the waist-around direction, the pair of tilted lines go up toward a side of the waist opening from the both edge lines to the center line, and the center line connects between the both tilted lines; a crotch edge of the dorsal member comprises both edge lines, a pair of tilted lines and a center line, the both edge lines are approximately parallel in the waist-around direction, the pair of the tilted lines go down toward an opposite side of the waist opening from the both edge lines to the center line, and the center line connects between the both tilted lines (12c,12c); the first leg-surrounding elastic body (203c, 403c) comprises both edge portions, a pair of tilted portions and a central portion, the both edge portions are disposed along the both edge lines in the ventral member and are approximately parallel in the waist-around direction, the pair of the tilted portions go up toward a side of the waist opening of the ventral member from the both edge portions to the central portion and are extended slantingly upward in a leaving direction from the crotch edge of the ventral member in an area overlapped with the crotch member of the ventral member, and the central portion connects between the both tilted portions; and the second leg-surrounding elastic body (203d, 403d) comprises both edge portions, a pair of tilted portions and a central portion, the both edge portions are disposed along the both edge lines in the dorsal member and are approximately parallel in the waist-around direction, and the pair of the tilted portions are extended slantingly downward an opposite side of the waist opening of the dorsal member in an approaching direction from the both edge portions to the center line of the dorsal member. a ventral member; a dorsal member; a crotch member that bridges the ventral member and the dorsal member bonded at center portions of the ventral member and the dorsal member; a waist opening surrounded by the ventral member and the dorsal member, wherein right and left side edges of the ventral member and right and left side edges of the dorsal member being bonded; right and left leg openings surrounded by the ventral member, the dorsal member and the crotch member; waist elastic bodies (103a, 103b) extended on the ventral member and the dorsal member in a waist-around direction; a first leg-surrounding elastic body (203c, 403c) extended at least on the ventral member around the right and left leg openings; and a second leg-surrounding elastic body (203d, 403d) extended at least on the dorsal member around the right and left leg openings; characterized in that a crotch edge of the ventral member comprises both edge lines, a pair of tilted lines and a center line, the both edge lines are approximately parallel in the waist-around direction, the pair of tilted lines go up toward a side of the waist opening from the both edge lines to the center line, and the center line connects between the both tilted lines; a crotch edge of the dorsal member comprises both edge lines, a pair of tilted lines and a center line, the both edge lines are approximately parallel in the waist-around direction, the pair of the tilted lines go down toward an opposite side of the waist opening from the both edge lines to the center line, and the center line connects between the both tilted lines (12c,12c); the first leg-surrounding elastic body (203c, 403c) comprises both edge portions, a pair of tilted portions and a central portion, the both edge portions are disposed along the both edge lines in the ventral member and are approximately parallel in the waist-around direction, the pair of the tilted portions go up toward a side of the waist opening of the ventral member from the both edge portions to the central portion and are extended slantingly upward in a leaving direction from the crotch edge of the ventral member in an area overlapped with the crotch member of the ventral member, and the central portion connects between the both tilted portions; and the second leg-surrounding elastic body (203d, 403d) comprises both edge portions, a pair of tilted portions and a central portion, the both edge portions are disposed along the both edge lines in the dorsal member and are approximately parallel in the waist-around direction, and the pair of the tilted portions are extended slantingly downward an opposite side of the waist opening of the dorsal member in an approaching direction from the both edge portions to the center line of the dorsal member.