A disposable diaper is provided which includes an absorber, a top sheet which is at least partially formed of a liquid permeable material disposed to cover an upper surface of the absorber, a back sheet formed of a liquid impermeable material disposed to cover a lower surface of the absorber, a skin contact sheet disposed above the top sheet and having a stool passing opening capable of passing a stool therethrough formed therein, and a urine/stool separation wall formed of a breathable water repellent sheet disposed in a space between the skin contact sheet and the top sheet so that the space is separated into a front body part side space and a back body part side space.