A vacuum valve includes a valve flange having a first port, a second port, and a valve seat in a space between the first port and the second port, a valve body in the valve flange, the valve body having a contact surface facing the valve seat, and the valve body being moveable to have the contact surface contact the valve seat and to be separated from the valve seat, a disk on the contact surface of the valve body, the disk having an inclined surface inclined toward the second port, and an actuator connected to the valve flange, the actuator being configured to apply a driving force to the valve body to move the contact surface of the valve body into or out of contact with the valve seat.