PURPOSE: To provide a carburetor device wherein reducing fuel in a float chamber during stopping an engine can be prevented easily without increasing a time of manufacture and a cost.

CONSTITUTION: A device is constituted by providing a float chamber 4 supplied with fuel from a fuel tank 9 during driving an engine through a fuel supply pipe 6, storing a float 13 in the float chamber 4, providing an overflow pipe 11 and an air vent 12 with one end opened respectively to the float chamber 4, providing a fuel supply valve 8 of holding a fuel oil level in the float chamber during driving the engine to almost a fixed level in the float 13, and providing a valve means 15 of closing the overflow pipe 11, when an oil level of fuel in the float chamber 4 is decreased lower than a prescribed position, in the float 13.