To provide a carburetor for a two-stroke stratified scavenging internal combustion engine that improves the accelerating characteristic of an engine without degrading an exhaust gas component.

An end flange 3 of a carburetor body 2 has a right-left pair of through holes 4, in which bolts are inserted to connect it to an intake port of an engine. The carburetor body has a scavenging air passage 9 and a mixture passage 10 passing in the respective upper and lower portions. The mixture passage is connected to an intake port of a crankcase of the engine via a check valve, and the air passage is connected to the midstream of a scavenging passage connecting the crankcase of the engine and a scavenging port in the bottom of a combustion chamber openable near the bottom dead center of a piston. The scavenging air passage and the mixture passage are provided with respective throttle valves. A groove passage 12 connecting the scavenging air passage and the mixture passage is formed in an outlet-side sidewall surface of the carburetor body.