A dual gate valve includes two valve plates that open and close two openings of a valve box, a support bar that supports the two valve plates, a valve rod connected to the support bar, and an operation unit that performs an open and close operation of the two valve plates via the valve rod. The support bar and the valve plate linearly and elongatedly extend in a lateral direction perpendicular to a central axis of the valve rod. The valve rod is connected to a central portion in the long direction of the support bar, and one and the other of the two valve plates are tiltably attached to one end and the other end in the long direction of the support bar via elastic members, respectively.