An underpants-type disposable diaper comprising: an outer member, which is extending from a front body to a back body as one unit, or outer members, which are separately provided on the front body and the back body; an inner member, which has a liquid pervious top sheet positioned on a front surface side, a liquid impervious sheet positioned on a back surface side, and an absorber interposed therebetween, which extends in the front-back direction from the front body to the back body, and which is joined to the outer member; and three-dimensional gathers, which are provided on both sides in the width direction of the inner member, wherein each of the three-dimensional gathers includes a main unit section positioned on each of both side portions of the inner member, fallen portions located on the front and back end portions of the main unit section and fixed in a fallen state, a non-fixed free portion located between the fallen portions in the main unit section, and a gather elastic member attached to the free portion, such that the free portion stands up by a contraction force of the gather elastic member, the fallen portion has a fallen non-stretchable portion to which the contraction force of the gather elastic member does not act, and a character representation is printed at a position in the fallen non-stretchable portion of the inner member, and the character representation is made visible on the inside of the diaper, wherein the outer member has a stretchable region, which is stretchable in the width direction, at a position corresponding to the character representation in the front-back direction, and each of both side portions of the inner member in the width direction including at least a part of the character representation is not joined to the outer member. which is extending from a front body to a back body as one unit, or outer members, which are separately provided on the front body and the back body; an inner member, which has a liquid pervious top sheet positioned on a front surface side, a liquid impervious sheet positioned on a back surface side, and an absorber interposed therebetween, which extends in the front-back direction from the front body to the back body, and which is joined to the outer member; and three-dimensional gathers, which are provided on both sides in the width direction of the inner member, wherein each of the three-dimensional gathers includes a main unit section positioned on each of both side portions of the inner member, fallen portions located on the front and back end portions of the main unit section and fixed in a fallen state, a non-fixed free portion located between the fallen portions in the main unit section, and a gather elastic member attached to the free portion, such that the free portion stands up by a contraction force of the gather elastic member, the fallen portion has a fallen non-stretchable portion to which the contraction force of the gather elastic member does not act, and a character representation is printed at a position in the fallen non-stretchable portion of the inner member, and the character representation is made visible on the inside of the diaper, wherein the outer member has a stretchable region, which is stretchable in the width direction, at a position corresponding to the character representation in the front-back direction, and each of both side portions of the inner member in the width direction including at least a part of the character representation is not joined to the outer member.