PROBLEM TO BE SOLVED: To easily expand a waist opening of an underpants type disposable diaper to a lateral direction for facilitating wearing of the diaper.SOLUTION: There is provided the underpants type disposable diaper comprising a vertical direction and a lateral direction which are orthogonal each other, and a cross direction, comprising a ventral part, a back part, a waist opening and a pair of leg surrounding openings. The ventral part and the back part have elasticity in the lateral direction. The ventral part and the back part are overlapped in the cross direction. On each end of the lateral direction, the ventral part and back part are continuous. At least one upper edge part out of an upper edge part which is the waist opening on the ventral part and an upper edge part which is the waist opening on the back part, has only one cut part extending downward on a position inside in the lateral direction of the respective end. When the diaper is viewed from the cross direction, the upper edge part on the ventral part and the upper edge part on the back part are positioned on a position below a virtual line connecting upper ends of the respective ends, or on the virtual line, over whole length of the lateral direction.SELECTED DRAWING: Figure 4ACOPYRIGHT: (C)2017,JPO&INPIT
