The insulating panel dowel has a plate (2) and a slotted hollow shank (1) which can be opened out by a spreader nail (12) capable of being driven into the core bore (16) of the hollow shank (1). The hollow shank (1) extends through the insulation (14) resting on the fixing base (8). In this bridging region (17), the core bore (16) has a narrowing which opens out the hollow shank in front of the drill-hole mouth (9) as the spreader nail (12) is driven in, and the dowel is prevented from penetrating further into the drill hole (10). <IMAGE>
