The present invention is a stretchable sheet manufacturing method for continuously manufacturing a stretchable sheet (3) configured by affixing a thread-shaped elastic body (7) in a stretched state between a pair of belt-shaped sheets (50, 60), and comprises: a supply step for introducing the paid out thread-shaped elastic body (7) in the stretched state into an elastic body winding means (14) a conveyance step for continuously winding the thread-shaped elastic body (7) on a thread conveyance longitudinal structure (12, 13) using the elastic body winding means (14) and conveying the wound thread-shaped elastic body in the longitudinal direction of the structure (12, 14) and an integration step for sandwiching and affixing the thread-shaped elastic body (7) between the sheets (50, 60). In the supply step, the thread-shaped elastic body (7) is introduced into the elastic body winding means (14) at a speed equal to or higher than the speed at which the thread-shaped elastic body is wound on a pair of conveyance belts (12, 13), by a speed adjustment means (15B) disposed upstream from the elastic body winding means (14).
