The present invention provides a production method for an underpants-type disposable diaper in space-saving and simple facilities while reducing the risk of occurrence of wrinkles, including: supplying a continuous sheet material (12S) in the continuous direction thereof； disposing resilient and elastic members (15 to 18) for imparting elasticity to a ventral side outer body (12F) and a dorsal side outer body (12B) at a CD direction intermediate portion (12c) of the sheet material (12S)； folding CD direction one side and other side parts across the CD direction intermediate portion (12c) toward the side of the CD direction intermediate portion (12c) with the resilient and elastic members (15 to 18), sandwiching and fixing the resilient and elastic members (15 to 18) in the folded sheet material (12s), and joining together the folded parts and the CD direction intermediate portion (12c) to form a continuous elastic belt； cutting the elastic belt at a CD direction intermediate position to obtain a dorsal side elastic belt (12b) and a ventral side elastic belt (12f), and then assembling an inner body (200) to the dorsal side elastic belt (12b) and the ventral side elastic belt (12f).
