A disposable diaper according to the invention comprises a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive central absorbent core interposed between said topsheet and said backsheet, said disposable diaper being formed in a substantially vertically elongated configuration and having a stomach side, a back side and a crotch region positioned between said stomach side and said back side, wherein a second absorbent core is disposed at an outside region of each opposite left (or right) side edge of said central absorbent core at said crotch region along a longitudinal direction of said diaper, a basis weight of an absorbent core disposed at an intermediate region between said central absorbent core and each of said second absorbent cores is smaller than a basis weight of any of said absorbent cores located at the region where said central absorbent core is disposed and at the region where each of said second absorbent cores is disposed, and a pair of axes of flexibility are formed on opposite side portions of said central absorbent core along a longitudinal direction.
