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).
