PURPOSE: To reduce the outer dimensions of sound insulated tank by placing the common oil lead pipe at the area near the sound insulated tank so that it becomes a part of the side wall thereof.

CONSTITUTION: The common oil lead pipe 5 is formed longer than the longitudinal (horizontal) dimension of side wall of the sound insulated tank 2 in the side where the common oil lead pipe 5 is provided and integrated in such a way as forming a part of the wall at the upper and lower portions of side wall of the sound insulated tank 2. The one end portion of the common oil lead pipe 5 is provided with the oil receiving port 15 while the other end with the oil sending port 16. In addition, both oil receiving port 15 and oil sending port 16 are also formed in the side of expansion joint 4 and are connected to the upper and lower portions of the tank 1 via the expansion joint 4 and connecting pipe 9, which is connected to the expansion joint 4 provided within the sound insulating wall window 13 formed at the wall, passing through the side wall of the sound insulated tank 2 orthogonally crossing the side wall surface of the sound insulated tank 2 wherein the common oil lead pipe 5 is provided.