Abstract: A vacuum valve comprises a housing having an inlet passage and a discharge passage with a valve seat defined within the housing between the inlet and discharge passages. A valve disc is engageable on the seat to close off the communication between the valve inlet passage and the discharge passage. An extension is formed on the top face of the valve disc adjacent each side edge and a lever member has an arm portion at each side which engages through the extension and which is receivable in a groove defined in the housing above the valve seat. A valve drive member is connected to move the valve disc toward and away from its seat and during the closing movement it acts on the lever member centrally to cause the outer arm portions to move outwardly and engage into the receiving groove and to both hold the valve against withdrawal from the valve seat and to aid in its pressing down against the seat in tight sealing engagement therewith.