A valve apparatus includes a valve block with a main flow path, a first valve installed on the valve block and connected to the main flow path so that when the first valve turns on, a first fluid is supplied from the main flow path to a process chamber via the first valve, and a second valve installed on the valve block and connected to the main flow path so that when the first valve turns off and the second valve turns on, a second fluid is supplied from the main flow path to a waste gas treatment system via the second valve. The main flow path is disposed parallel to a central axis passing through a center of the valve block and two opposing surfaces of the valve block perpendicularly thereto. The main flow path is disposed to be offset from the central axis toward the first valve.