To provide a working ship improving efficiency of energy by effectively using cooling water to be transported from a ship body to a cooler of a work machine.

A working ship includes a ship body 2, a work machine 3 provided on the ship body 2, and a tank 24 provided in the ship body 2 and storing cooling water. The working ship also includes a cooling water circulation passage 20 which transports the cooling water stored in the tank 24 to a cooler 11 of the work machine 3, and transports the cooling water having passed through the cooler 11 to the tank 24. The cooling water in the cooling water circulation passage 20 is circulated by a cooling water pump 23 interposed in the cooling water circulation passage 20. The working ship further includes a generator 28 which is interposed in the cooling water circulation passage 20 after passing the cooler 11, and before reaching the tank 24 and generates the power by the water flow flowing in the cooling water circulation passage 20.