A device for fastening permanently or temporarily implantable medical devices includes a main body (1) having a first end (1a) and a second end (1b), a flexible and extensible body section (2) therebetween, and a first inflexible and inextensible body support (3) which is fixedly attached to the body section (2) at the second end (1b) of the main body (1), whereby the extensible section (2) can be converted from an unextended state to an extended state in which it is lengthened in comparison with the unextended state. At least one first flexible finger-shaped anchor (4) protrudes away from the main body (1) and is attached to the first body support (3) at an anchor mount (4a). At least one first flexible retraction device (5) is provided for retraction of a respective first anchoring means (4), wherein the retraction device (5) is connected to the body section (2) and to the anchor (4). On conversion of the body section (2) from the unextended state to the extended state, the retraction device (5) does not expand, so that the respective anchors (4) are moved in the direction of the main body (1).