In a gate valve including a valve plate connected to a valve plate mounting portion of at a tip end of a valve rod with a connecting plate and configured to open and close a communicating hole of a valve box with the valve plate, the valve plate includes a mounting hole, a joint flat surfaces coming into press-contact with each other, the valve rod includes a depressed-shaped joint shoulder portion, the joint shoulder portion is formed with an inclined surface configured to guide the valve plate in the direction in which the joint flat surfaces are brought into press-contact with each other, and the coupling plate couples the valve plate and the valve rod with each other.