Cooling device for power source for ship propulsion device

A cooling device for a power source for a ship propulsion device comprising:

• a cooling water route that supplies water pumped up from underwater to a cooling water passage to cool the power source and discharges cooling water after the coding from the cooling water passage to outside, foreign matters with sizes that cause clogging of the cooling water route having been removed from the cooling water flowing through the cooling water route;
• and
• a filtration device that is provided in the cooling water route to filtrate foreign matters remaining in the cooling water,
• wherein the filtration device comprises a cartridge-type filtration device,
• wherein the filtration device is configured to incorporates a filter for filtration disposed in a main water passage and a valve member configured to open and close a bypass water passage, and
• wherein the filtration device, when clogging occurs therein during the power source been being cooled, is configured to open the valve member opens to cause the cooling water to flow, via the bypass water passage, from the upstream side to the downstream side of the cooling water route.