To feed liquid fuel added with an additive and an ordinary liquid fuel independently in a simple structure.

An additive tank 5 containing an addition agent is detachably mounted on a main body 2, and an additive flow passage 2D leading the additive in the additive tank 5 to a flow passage 2A is formed at a position in the main body 2, which is opposed to an outlet port 5A of the additive tank 5. A valve 16 for the additive, which allows the additive to be introduced, or checks it from being introduced, into the flow passage 2A, is provided in the additive flow passage 2D, and a conjunction mechanism 4B for allowing a fuel flow rate regulating value 3 provided in the main body 2 to operate in conjunction with the valve 16 for the additive is provided to an operation lever 4 for opening and operating the fuel flow rate regualating valve 3.