[Problem] To increase ventilation in an area where a tuck is formed in a disposable diaper separated into a front panel outer body, a rear panel outer body, and an absorbent body. [Solution] A disposable diaper equipped with a front panel outer body (10), a rear panel outer body (20), and an absorbent body (30), wherein: the absorbent body (30) has an absorbing part (31), a liquid-permeable top-sheet (32), and a liquid-impermeable back-sheet (33) that covers; the absorbent body (30) is connected, via a connecting part (40) having a peak fold and a valley fold that extend in the widthwise direction of the diaper, to the front panel outer body (10) and/or the rear panel outer body (20); and the absorbing part (31) has recesses (38) formed therein that recess in the thickness direction of the absorbing part (31) or through-holes formed therein which pass therethrough in the thickness direction in at least an end section thereof where the connecting part (40) is positioned on the front panel outer body (10) side and/or on the rear panel outer body (20) side.