PROBLEM TO BE SOLVED: To provide a method of manufacturing a disposable trunks-type diaper that does not generate cut-off piece removed from a crotch portion.SOLUTION: A plurality of sheet pieces S to be a skirt part 50 are arranged so as to straddle continuous webs W transported in parallel and intermittently in a transport direction D1, a pair of continuous webs W are displaced so that a second edge part E2 of one of the pair of continuous webs W and a second edge part E2 of the other web come into contact with each other, and an absorbent body 40 is sequentially intermittently disposed between the adjacent sheet pieces S. A compound material W4 is folded in two in the transport direction D1 so that the pair of continuous webs W overlap each other, and between two adjacent absorbent bodies 40, the sheet piece S and the pair of continuous webs W are cut in a width direction D2 and sealed. The continuous webs W are sealed at a crotch portion 30, and a side edge part E3 close to the crotch portion 30 in each sheet piece S is sealed.
