Abstract: The invention relates to a venting unit for a die casting device which has a mold cavity that is adapted to be filled with liquid casting material and a gas suction device that is connected to the mold cavity for extracting gas from the mold cavity by suction, the venting unit comprising a flow labyrinth, the inlet of which is adapted to be connected to the mold cavity and the outlet of which is adapted to be connected to the gas suction device. In order to develop the venting unit in such a way that it makes improved evacuation of the mold cavity possible without the risk that liquid casting material can escape from the venting unit, it is proposed according to the invention that the flow cross-section of the flow labyrinth is variable. Furthermore, a die casting device with a venting unit of this kind is proposed.