The present invention provides a manufacturing device for a flexible sheet and a manufacturing method for a flexible sheet. The manufacturing device for the flexible sheet comprises: a joint mechanism for jointing a pair of continuous sheets with a filiform elastic component in the state of sandwiching the filiform elastic component which extends along a direction intersected with a continuous direction of the continuous sheets, i.e., a width direction, between the pair of continuous sheets a conveying mechanism for conveying the wound filiform elastic component to the position between the pair of continuous sheets a winding mechanism for continuously and successively releasing the filiform elastic components and winding the filiform elastic component onto the conveying mechanism in an extended state a tension adjusting mechanism for adjusting the filiform elastic component to a required tension and continuously and successively releasing the filiform elastic components and a speed adjusting mechanism for continuously and successively releasing the filiform elastic components successively released from the tension adjusting mechanism to the winding mechanism at a second speed which is slower than a first speed at which the winding mechanism winds the filiform elastic component onto the conveying mechanism. The deviation between an extended rate of the filiform elastic component between the pair of continuous sheets and an object extended rate is suppressed.
