PROBLEM TO BE SOLVED: To provide a disposable diaper which can suppress leakage of body fluids by a rising leg side expanding and contracting part located on an inner side of a leg opening part in a product width direction.SOLUTION: A leg side expanding and contracting part 80 of a disposable diaper 10 includes: a contracting part 84 a first joining part 81A which is provided on an outer side of the contracting part in a product width direction and is joined to a back surface side member located on a skin non-contact surface side rather than the leg side expanding and contracting part in an intermediate region located between a leg expanding and contracting part and a crotch expanding and contracting part and a second joining part 81B which is provided on both outer sides of the contracting part in a product longitudinal direction and is joined to the back surface side member. The intermediate region has a rate of expansion and contraction that is lower than that of the crotch expanding and contracting part and is lower than that of the leg expanding and contracting part.
