To provide a fire suppression system configured to minimize environmental load.

The fire suppression system 20 includes a main gas container 22 and a second gas container 24 containing inert gas. The gas container 22 communicates with a manifold 23 and a flow line 25 situated on the downstream of the manifold 23. The flow line 25 includes a pressure regulating valve 30 controlled by a pneumatic control unit 34. A high-pressure gas supply unit 32 supplies control gas to the pneumatic control unit 34 through a valve 36. The pneumatic control unit 34 includes a flow line 40 corresponding to a valve 48 of each compartment A, B, C, and a tap 42 for guiding the control gas to the valve 30 and each compartment A, B, C to control the pressure of the control gas delivered to the valve 30. The fire suppression system further includes a valve corresponding to the main container, and the valve switches the main container to the second container when the pressure in the main container drops to a predetermined amount or less. This switching is performed by pneumatic control.