A stretchable composite sheet (20) used in a waist region of a disposable wearing article. The stretchable composite sheet (20) has a stretchable sheet (21) and a non-stretchable sheet (22), and the stretchable sheet (21) is stretched. Nip roll mechanisms (101, 102) are respectively arranged on one end side in the stretch direction (SD) and the other end side, and the stretchable sheet (21) is bonded to the non-stretchable sheet (22) by the nip roll mechanisms (101, 102) with the stretchable sheet (21) contracted in the direction (CD) orthogonal to the stretching direction (SD). The above processes provide the stretchable composite sheet with basic weight change regions (211, 212) in which the basis weight of the stretchable sheet (21) is changed depending on stretch conditions of the stretchable sheet (21). The basic weight of the basic weight change regions (211, 212) is greater than that of a center region (210) of the stretchable composite sheet (20).