An underpants-type disposable diaper comprising: an outer body forming individually or integrally a front body and a back body; and an absorber provided on the inner side of the outer body ranging from the front body to the back body, the outer body of the front body and the outer body of the back body being joined together at both side edges to form side seal portions, thereby forming a waist opening and a pair of right and left leg openings, wherein a vertical stretchable part vertically extending and contracting in length is provided in a vertical intermediate portion of the absorber in the front body, the vertical stretchable part being a slit or a low-basis weight part continuous on the entire absorber in the width direction the outer body of the front body has a portion overlapping the vertical stretchable part, with side sections extending from both lateral sides of the portion, and a waist opening, lifting elastic members capable of exerting a contraction force lifting a portion of the vertical stretchable part on a rear side of a front end portion towards both sides in the width-direction, and obliquely upward towards the sides when the diaper is worn, are provided in the outer body of the front body closer to its lateral sides than to a central portion in the width-direction of the absorber, the vertical stretchable part vertically extending and contracting in length by elastic extension and contraction of the lifting elastic members, the lifting elastic members including leg opening elastic members composed of elongated elastic members extending laterally along the width direction from positions overlapping the side parts of the absorber and being provided in the outer body of the front body at leg opening portions in vertical ranges corresponding to the leg openings on the rear side of the front end portion of the vertical stretchable part, and the leg opening elastic members being oriented obliquely in an upward and lateral direction when the diaper is worn. an outer body forming individually or integrally a front body and a back body; and an absorber provided on the inner side of the outer body ranging from the front body to the back body, the outer body of the front body and the outer body of the back body being joined together at both side edges to form side seal portions, thereby forming a waist opening and a pair of right and left leg openings, wherein a vertical stretchable part vertically extending and contracting in length is provided in a vertical intermediate portion of the absorber in the front body, the vertical stretchable part being a slit or a low-basis weight part continuous on the entire absorber in the width direction the outer body of the front body has a portion overlapping the vertical stretchable part, with side sections extending from both lateral sides of the portion, and a waist opening, lifting elastic members capable of exerting a contraction force lifting a portion of the vertical stretchable part on a rear side of a front end portion towards both sides in the width-direction, and obliquely upward towards the sides when the diaper is worn, are provided in the outer body of the front body closer to its lateral sides than to a central portion in the width-direction of the absorber, the vertical stretchable part vertically extending and contracting in length by elastic extension and contraction of the lifting elastic members, the lifting elastic members including leg opening elastic members composed of elongated elastic members extending laterally along the width direction from positions overlapping the side parts of the absorber and being provided in the outer body of the front body at leg opening portions in vertical ranges corresponding to the leg openings on the rear side of the front end portion of the vertical stretchable part, and the leg opening elastic members being oriented obliquely in an upward and lateral direction when the diaper is worn.