A stretchable composite sheet used in a waist region of a disposable wearing article. The stretchable composite sheet has a stretchable sheet and a non-stretchable sheet, and the stretchable sheet is stretched. Nip roll mechanisms are respectively arranged on one end side in the stretch direction (SD) and the other end side, and the stretchable sheet is bonded to the non-stretchable sheet by the nip roll mechanisms with the stretchable sheet contracted in the direction (CD) orthogonal to the stretching direction (SD). The above processes provide the stretchable composite sheet with basic weight change regions in which the basis weight of the stretchable sheet is changed depending on stretch conditions of the stretchable sheet. The basic weight of the basic weight change regions is greater than that of a center region of the stretchable composite sheet.