The invention relates to a gate unit for gas-tight sealing of two adjacent high temperature zones within a high temperature oven, comprising a gate panel displaceable between an open position and a closed position within a guide structure. At least one sealing element is transported with the gate panel. Protecting means can be transported by the gate panel over at least one part of a transport path of the same, by which at least one segment of the sealing element can be protected over at least one part of the displacement path of the gate panel against influences harmful to the sealing element particularly against radiant heat. The invention further relates to a high temperature oven having an oven tunnel comprising a first high temperature zone and a second high temperature zone. The gate panel is disposed in a transition region between the first and the second high temperature zones.