An integrated apparatus includes: a gas-liquid separator that separates a gas and a liquid from a gas-liquid mixture fluid; a diluter disposed below the gas-liquid separator; and a communication pipe that communicates between the gas-liquid separator and the diluter, and that is disposed at a predetermined angle to a horizontal direction, and that introduces at least the liquid separated from the gas-liquid mixture fluid, into the diluter. The gas-liquid separator, the diluter, and the communication pipe are integrated.