To improve the waterproofing and the dust resistance for a carburetor of an air-fuel mixture feeding device and to reduce the cost of the air-fuel mixture feeding device.

An engine 25 is provided with the air-fuel mixture feeding device 27 equipped with an air cleaner box 28. The air cleaner box 28 is provided with an input side suction pipe 29 communicating outward and an output side suction pipe 30 communicating to a combustion chamber 15a of the engine 25. An air filter 31 is housed in the air cleaner box 28 partitioning a dust chamber 31a and a clean chamber 31b. Because the carburetor 32 for feeding air-fuel mixture into the combustion chamber 15a is housed in the clean chamber 31b of the air cleaner box 28, the carburetor 32 can improve the waterproofing and the dust resistance without being exposed to water and dust, waterproofing structure and dust resistance structure of the carburetor 32 can be simplified, and the cost of the air-fuel mixture feeding device 27 can be reduced.