PROBLEM TO BE SOLVED: To provide an absorbent article which can effectively prevent liquid leakage.SOLUTION: An absorbent article includes a top sheet 10, a back sheet 20, an absorber 30, and a pair of side sheets 40. The back sheet 20 has an extension part 22 extending outside in a width direction to both end edges 11 in a width direction of the top sheet 10. In the pair of side sheets 40, a part positioned outside in the width direction of a first joint part A to be a joint point with the top sheet 10 is joined to the extension part 22 of the back sheet 20 across in a second joint part B in a longitudinal direction of the extension part 22. The pair of side sheets 40 are overlapped in two layers or more on a surface side opposite to the skin of the back sheet 20 at a part joined to the extension part 22 of the back sheet 20 by at least the second joint part B.
