A disposable diaper (1A,1B) comprising: a front waist region; a rear waist region; a crotch region extending between said waist regions (5,7); a liquid-pervious topsheet facing the wearer's skin; a liquid-impervious backsheet facing away from the wearer's skin; and a liquid-absorbent core interposed between said top- and backsheets (2,3); said diaper (1A,1B) being contoured by longitudinally opposite end portions extending in a transverse direction outside longitudinally opposite ends of said core and transversely opposite side edge portions extending in a longitudinal direction outside transversely opposite side edges of said core wherein said front and rear waist regions (5,7) are connected to each other by means of fastening means when said diaper (1A,1B) is put on; and of said front and rear waist regions (5,7), at least said rear waist region includes an elastically stretchable waist area extending in the transverse direction along its end and elastically stretchable wing areas extending outward from its transversely opposite side edge portions in the transverse direction, said transversely opposite side edge portions of said rear waist region lying between said stretchable waist area and said stretchable wing areas, the stretchable elasticity of said elastically stretchable waist area being created by a tape-like first elastic member contractibly attached to said waist region along its end and the stretchable elasticity of said elastically stretchable wing areas being created by stretchy sheets separately of said top- and backsheets (2,3), and the opposite side edge portions of said rear waist region being formed from transversely opposite side edge portions of said topsheet and transversely opposite side edge portions of said backsheet; characterized in that:- said stretchable wing areas have a transverse stretch stress higher than that of said stretchable waist area, the transversely opposite side edge portions of said rear waist region are substantially non-stretchable, and said stretchable waist area is not fully stretched before said stretchable wing areas are sufficiently stretched in the transverse direction, when said transverse stretch stresses are measured in accordance with methods as described in paragraphs, and of the description. a front waist region; a rear waist region; a crotch region extending between said waist regions (5,7); a liquid-pervious topsheet facing the wearer's skin; a liquid-impervious backsheet facing away from the wearer's skin; and a liquid-absorbent core interposed between said top- and backsheets (2,3); said diaper (1A,1B) being contoured by longitudinally opposite end portions extending in a transverse direction outside longitudinally opposite ends of said core and transversely opposite side edge portions extending in a longitudinal direction outside transversely opposite side edges of said core wherein said front and rear waist regions (5,7) are connected to each other by means of fastening means when said diaper (1A,1B) is put on; and of said front and rear waist regions (5,7), at least said rear waist region includes an elastically stretchable waist area extending in the transverse direction along its end and elastically stretchable wing areas extending outward from its transversely opposite side edge portions in the transverse direction, said transversely opposite side edge portions of said rear waist region lying between said stretchable waist area and said stretchable wing areas, the stretchable elasticity of said elastically stretchable waist area being created by a tape-like first elastic member contractibly attached to said waist region along its end and the stretchable elasticity of said elastically stretchable wing areas being created by stretchy sheets separately of said top- and backsheets (2,3), and the opposite side edge portions of said rear waist region being formed from transversely opposite side edge portions of said topsheet and transversely opposite side edge portions of said backsheet; characterized in that:- said stretchable wing areas have a transverse stretch stress higher than that of said stretchable waist area, the transversely opposite side edge portions of said rear waist region are substantially non-stretchable, and said stretchable waist area is not fully stretched before said stretchable wing areas are sufficiently stretched in the transverse direction, when said transverse stretch stresses are measured in accordance with methods as described in paragraphs, and of the description.