An absorbent article 1 having a liquid retentive absorbent layer and a liquid impermeable leak preventive layer and including, in its longitudinal direction, an excretion portion facing section A which is placed opposite a wearer's liquid excretion portion, when in wear, and a rear section B which is placed more on the back side than the excretion portion facing section A, when in wear, wherein a leak preventive wall 5 is disposed on opposite side portions in the longitudinal direction, the leak preventive wall 5 having a basal wall portion and a planar elastic expansible/contractible portion connected to an upper end portion of the basal wall portion and being raised in the excretion portion facing section A and in the rear section B, and wherein a distance from an upper end portion of the basal wall portion to the leak preventive layer in the rear section is shorter than a comparable distance in the excretion portion facing section A.