Waste gas treatment system of marine diesel engine

The invention provides a waste gas treatment system of a marine diesel engine, and the waste gas treatment system can reliably remove particulate matter and sulfur oxide contained in waste gas exhausted from the marine diesel engine. The waste gas treatment system comprises an electric dust collection device (7) collecting PM in the waste gas exhausted by the marine diesel engine, a seawater washer (9) for carrying out seawater spraying on the waste gas with the PM being removed by the electric dust collection device so as to remove SOx, a waste gas component detecting part (LA3) for detecting waste gas components obtained after treatment of the electric dust collection device and the seawater washer, a seawater component adjusting part (9C) for recycling seawater obtained after spraying of the seawater washer and adjusting the components, a seawater circulation part (9D) returning the seawater with the components being adjusted by the seawater component adjusting part to the seawater washer, and a waste gas