An elastically stretchable disposable wearing article has a front waist region, a rear waist region and a crotch region. This wearing article is formed with a first elastic zone, a second elastic zone and third elastic zones respectively exhibiting stretch stress adjusted to be decreased in this order. An elastically stretchable web is continuously fed in a machine direction, formed with pairs of slits in desired patterns so that two slits constituting each of the pairs may be symmetrically laid about a transversely middle zone of the web and then folded in a cross direction orthogonal to the machine direction so that the web may be alternately overlapped on itself about the transversely middle zone to form the wearing article.