A vacuum valve comprises a valve suction port flange; a valve exhaust port flange having a greater opening diameter than that of the valve suction port flange; a valve plate; a valve driver configured to slidably drive the valve plate between a closed position and an opening position; and a gas flow path region including an opening of the valve exhaust port flange and having a changing flow path sectional area. In the gas flow path region, a flow path sectional area of an upstream region end is set to an opening sectional area of the valve suction port flange, and increases toward the opening of the valve exhaust port flange.