Abstract: An insulating glass unit having at least two glass panes, a fastener for fixing the position of the glass panes and a sealing element for setting a distance between two neighboring panes and for gas-tight, lateral insulation of the pane intermediate space enclosed by the panes, the sealing element containing at least one gas-tight middle part and two lateral gap seals, each of which is situated in the area between one of the glass panes and the middle part, at least one diffusion-tight cushion, which is essentially made of an elastic material, being situated in the area between the two gap seals of the sealing element. The inner surfaces of the cushion preferably have a metal layer vapor-deposited on them. In a preferred embodiment, the fastener is a metal clamp externally enclosing the panes which enables the insulating glass unit to be manufactured essentially without adhesive.