A tape-type disposable diaper, comprising: a ventral part extending forward from the center in a front-back direction; a dorsal part extending backward from the center in the front-back direction; a crotch portion, both side edges of which extend from the middle in the front-back direction of the ventral part to the middle in the front-back direction of the dorsal part, both the side edges of the crotch portion passing through a width range of ± 5 mm away vertically from a direction intersecting with the front-back direction at a smaller angle less than ± 2 degrees; an absorber incorporated in a range including the crotch portion; wing parts extending outward in the width direction compared with the crotch portion in the ventral part and the dorsal part; and a connecting tape for detachably connecting the ventral part both sides of the dorsal part, wherein a lower edge (70, 75) of the wing part of the ventral part extends so as to be located obliquely outward toward the front side, the lower edge (70, 75) of the wing part of the ventral part has a first part located on the base edge side of the wing part and a second part located on the tip end side of the wing part, the range excluding at least both ends of the first part and the range excluding at least both ends of the second part are each a wavy portion having a plurality of valleys recessed inward, an obtuse side intersection angle between a tangent contacting both of adjacent valleys and the front-back direction in the wavy portion of the first part is 160 to 175 degrees, an obtuse side intersection angle between a tangent contacting both of adjacent valleys and the front-back direction in a wavy portion of the second part is 120 to 150 degrees, the dimension of the first part in the front-back direction is 0.15 to 0.30 times the dimension of the crotch portion in the front-back direction, and the dimension of the second part in the front-back direction is 0.10 to 0.25 times the dimension (M y) of the crotch portion in the front-back direction. a ventral part extending forward from the center in a front-back direction; a dorsal part extending backward from the center in the front-back direction; a crotch portion, both side edges of which extend from the middle in the front-back direction of the ventral part to the middle in the front-back direction of the dorsal part, both the side edges of the crotch portion passing through a width range of ± 5 mm away vertically from a direction intersecting with the front-back direction at a smaller angle less than ± 2 degrees; an absorber incorporated in a range including the crotch portion; wing parts extending outward in the width direction compared with the crotch portion in the ventral part and the dorsal part; and a connecting tape for detachably connecting the ventral part both sides of the dorsal part, wherein a lower edge (70, 75) of the wing part of the ventral part extends so as to be located obliquely outward toward the front side, the lower edge (70, 75) of the wing part of the ventral part has a first part located on the base edge side of the wing part and a second part located on the tip end side of the wing part, the range excluding at least both ends of the first part and the range excluding at least both ends of the second part are each a wavy portion having a plurality of valleys recessed inward, an obtuse side intersection angle between a tangent contacting both of adjacent valleys and the front-back direction in the wavy portion of the first part is 160 to 175 degrees, an obtuse side intersection angle between a tangent contacting both of adjacent valleys and the front-back direction in a wavy portion of the second part is 120 to 150 degrees, the dimension of the first part in the front-back direction is 0.15 to 0.30 times the dimension of the crotch portion in the front-back direction, and the dimension of the second part in the front-back direction is 0.10 to 0.25 times the dimension (M y) of the crotch portion in the front-back direction.