Abstract: A gate valve (1) is constructed for the simultaneous blocking or clearing of two rectangular passage openings (8,9) of two chamber walls (4,5) that are provided between two vacuum chambers (1,3) and aligned with one another. To this end, it has two valve plates (20, 21), which are a component of a slider (15), which is situated so that it can move with play from a position clearing the passage openings (8,9) to a position which closes the passage openings (8,9). To move the valve plates (20,21) to the closing setting against the passage openings (8,9) on the slider (15), at least one lifting element (24), which is acted on by pressure, is provided.