Abstract: [Problem] There is provided an exhaust system capable of sufficiently exhausting a fuel leakage gas leaked from a marine internal combustion engine without diffusing the fuel leakage gas into an engine room. [Solution] An exhaust system according to an aspect of the present disclosure includes: an exhaust duct provided above a marine internal combustion engine installed in an engine room of a ship; and a suction fan that sucks a fuel leakage gas leaking from the marine internal combustion engine into the inside of the exhaust duct from an engine upper unit side of the marine internal combustion engine. The exhaust duct exhausts the fuel leakage gas sucked by the suction fan to the outside of the engine.