This unfolding-type disposable diaper (1) has a longitudinal direction, a lateral direction, and a thickness direction that are orthogonal to each other, and has a first waist section (1a), a crotch section (1m), and a second waist section (1b) in a row in the longitudinal direction. Fastening tape (11, 11) fixed to each lateral end (1bsf, 1bsf) of the second waist section (1b) is engaged with the first waist section (1a), whereby a waist opening (1HB) and a pair of leg openings (1HL, 1HL) are formed. Cut-out lines (1c, 1c), which are for cutting out the parts (1bk, 1bk) of the second waist section (1b) to which the fastening tape (11, 11) is fixed, are formed in the unfolded diaper (1).
