A pants type disposable diaper having less gathers on the innermost side of a crotch region. In the crotch region (6) of the pants type disposable diaper (1), there is provided a bodily-fluid absorptive core material (26) located between a liquid-permeable inner surface-side sheet (23) and a liquid-impermeable outer surface-side sheet (24). On the inner side of the inner surface-side sheet (23) is provided an innermost sheet (21) which prevents contact between the inner surface-side sheet (23) and a wearers skin. The innermost sheet (21) has opposite ends in the front-rear direction (A), and portions near the opposite ends are joined to at least either the inner surface-side sheet (23) or the outer surface-side sheet (24). Further, the innermost sheet (21) has a tuck (36) located at a portion on the lateral centerline (P) of the diaper (1) and hanging toward the inner surface-side sheet (23).
