In an implantable device (1) for use in the human and/or animal body for closure or partial closure of defect openings (2), cavities, organ passages etc or for providing a defined communicating opening between walls, organs, cavities etc comprising a carrier structure (17) which in a primary form has a large ratio of length to transverse extent along an axis (x) and in a secondary form has a smaller ratio of length to transverse extent along the axis (x), wherein the carrier structure (17) has a proximal and a distal portion (10, 11) and is formed in the manner of a weft and/or mesh and/or layered cloth and/or gauze, at least the one portion (11) in the secondary form has a first sub-portion (14) facing outwardly away from the other portion (10) or towards same and to form at least one double-layer configuration a second sub-portion (13) which deploys first from the primary form into the secondary form and which is folded back in a direction towards the other portion (10) or inwardly on to the first sub-portion (14).
