An insulation holder (100, 1300) for connecting an insulation element to a structural element to be cast, wherein the insulation holder (100, 1300) features: an end section on the insulation element side, which is designed for being inserted into the insulation element in order to anchor itself therein; an end section on the structural element side, which lies opposite of the end section on the insulation element side and is designed for being cast into the structural element; an expansion mechanism, which is designed for expanding in the insulation element during the insertion of the end section on the insulation element side into the insulation element in order to anchor itself therein; wherein the expansion mechanism features an expansion stopping face, which is designed for striking against a boundary surface of the insulation element upon reaching a nominal depth (d) during the insertion of the end section on the insulation element side into the insulation element; wherein the expansion stopping face is realized in the form of a principal face of a stop plate, and wherein the principal face is oriented orthogonal to the inserting direction of the end section on the insulation element side into the insulation element; characterized in that the expansion mechanism is designed for triggering the expansion in the insulation element as the insertion of the end section on the insulation element side into the insulation element continues after the nominal depth (d) has been reached, wherein the expansion mechanism features expansion structures (116, 118), which are designed for separating, as well as for being spread apart by an expanding edge such that an undercut is formed, as the insertion continues. an end section on the insulation element side, which is designed for being inserted into the insulation element in order to anchor itself therein; an end section on the structural element side, which lies opposite of the end section on the insulation element side and is designed for being cast into the structural element; an expansion mechanism, which is designed for expanding in the insulation element during the insertion of the end section on the insulation element side into the insulation element in order to anchor itself therein; wherein the expansion mechanism features an expansion stopping face, which is designed for striking against a boundary surface of the insulation element upon reaching a nominal depth (d) during the insertion of the end section on the insulation element side into the insulation element; wherein the expansion stopping face is realized in the form of a principal face of a stop plate, and wherein the principal face is oriented orthogonal to the inserting direction of the end section on the insulation element side into the insulation element; characterized in that the expansion mechanism is designed for triggering the expansion in the insulation element as the insertion of the end section on the insulation element side into the insulation element continues after the nominal depth (d) has been reached, wherein the expansion mechanism features expansion structures (116, 118), which are designed for separating, as well as for being spread apart by an expanding edge such that an undercut is formed, as the insertion continues.