A folding unit (120) extends in the MD2 direction and has a central guide (121) that comes into contact with the bottom of the crotch part (13), a pair of side guides (122) that come into contact with the front waist (11) and the rear waist (12), and a layering roller (150) that lays the front waist (11) and the rear waist (12) one on the other. The space between the pair of side guides (122) becomes narrower in the downstream conveyance direction. The ends (122de) of the side guides (122) are located further upstream in the conveyance direction than the end (121de) of the central guide (121). The layering roller (150) lays the front waist (11) and the back waist (12) one on the other further downstream in the conveyance direction than the side guides (122).