A method for producing a disposable worn article and a laminated stretchable sheet of the present invention includes: a step of forming stretched elastic sheet pieces F1 from a continuous elastic sheet; a step of carrying continuous webs Wa and Wb to be torso portions; a step of placing the elastic sheet pieces F1 intermittently on the continuous webs Wa and Wb; a step of bonding opposite end portions of the elastic sheet pieces F1 in the longitudinal direction to the continuous webs Wa and Wb by an adhesive, during the placement; an ultrasonic attachment step of forming a laminated stretchable sheet in an overlap portion between an intermediate portion between the opposite end portions of the elastic sheet piece F1 and the continuous webs; a placement step of placing core portions C, each of which forms a crotch portion 33, between adjacent ones of the elastic sheet pieces F1; and a step of cutting off the laminated stretchable sheet between adjacent ones of the core portions C.