This interface connection through a hole (2) in a high-temperature-resistant and vacuum-proof insulating part (1), particularly of ceramic, glass, or a single crystal, consists of a metallic lead (4, 17) inserted into the hole (2) and having a coefficient of thermal expansion less than that of the insulating part (1), wherein at least one end of the lead, if it is flush with at least one surface of the insulating part, is covered with active brazing material which high-vacuum-seals it to the insulating part, or, if it projects beyond at least one surface of the insulating part, is high-vacuum-sealed to the insulating part by means of ring-shaped active brazing material (5'), since in the liquid phase, the active brazing material moves into the gap between the wall of the hole (2) and the lead (4, 17) due to capillary action. Thus, the available materials (insulating material, metals having a smaller coefficient of thermal expansion than the insulating part, active brazing materials) can be used in a different and novel manner such that the use of a lead covered with active brazing material can be dispensed with.