The present invention relates to a disposable diaper (1) provided with a pair of leakage prevention partitions (4) that each include a free end (4FP). Each leakage prevention partition is provided with, at least at the free end, a first sheet section (6U) and a second sheet section (6L) that overlap one another, and an elastic member (7) that is disposed between said sheet sections. The first sheet section and the second sheet section overlap such that undulating areas (41) of the first sheet section and undulating areas of the second sheet section are adjacent to one another, and non-undulating areas (43) of the first sheet section and non-undulating areas of the second sheet section are separated from one another, and also such that, with respect to the short-side direction of the leakage prevention partitions, the undulating areas of the first sheet section and the undulating areas of the second sheet section are aligned with one another, and the non-undulating areas of the first sheet section and the non-undulating areas of the second sheet section are aligned with one another.
