To provide an outboard motor supplying fuel to an injector by a simple structure.

A ship propeller includes: an engine 26; the injector 58 provided to the engine 26; a fluid-tight and airtight fuel forcible feeding pump 74 pumping up fuel stored in a main fuel tank 22 provided to a ship and forcibly feeding it to the injector 58; a first fuel supply path fluid-tightly and airtightly connecting the main fuel tank 22 and fuel forcible feeding pump 74 and being always in a vacuum state during operation of the engine 26; and a second fuel supply path fluid-tightly and airtightly connecting the fuel forcible feeding pump 74 and injector 58 and always pressurized during the operation of the engine 26.