A rotary carburetor which is used in a stratified scavenging two-stroke internal combustion engine in which at least one scavenging passage is provided on each side of a mixture inlet, comprising: a block-like body having a cylindrical bore with a center of an axis; a valve element having a cylindrical form and rotatably contained in the bore; and a nozzle unit disposed in the valve element along the axis, wherein the valve element includes valve passages for air (20, 22) and a valve passage for mixture extending through the valve element in a direction across the axis, wherein the nozzle unit includes a port which is opened to the valve passage for mixture and ejects fuel, wherein the body includes an upstream body passage (10a, 11 a, 12a) communicating with the valve passages for air (20, 22) and the valve passage for mixture upstream of the valve element, and downstream body passages for air (10b, 12b) and a downstream body passage for mixture (11 b) respectively communicating with the valve passages for air (20, 22) and the valve passage for mixture downstream of the valve element, wherein the valve element is rotatable around the axis between an opened position and an closed position, wherein in the opened position, the valve passages for air (20, 22) and the valve passage for mixture respectively communicate with the downstream body passages for air (10b, 12b) and the downstream body passage for mixture, and the valve passages for air (20, 22) and the valve passage for mixture communicate with the upstream body passage (10a, 11 a, 12a), wherein in the closed position, the valve passages for air (20, 22) and the valve passage for mixture are respectively blocked off from the downstream body passages for air (10b, 12b) and the downstream body passage for mixture, and the valve passages for air (20, 22) and the valve passage for mixture are blocked off from the upstream body passage (10a, 11 a, 12a),wherein the rotary carburetor is a one-bore type rotary carburetor in which the valve passages for air (20, 22) and the valve passage for mixture are partitioned with plate-like valve partitions (24, 25), and the downstream body passages for air (10b, 12b) and the downstream body passage for mixture are partitioned with plate-like body partitions (14b, 15b), wherein two downstream body passages for air (10b, 12b) and two valve passages for air (20, 22) are provided, and are respectively disposed on the opposite sides of the downstream body passage for mixture (11 b) and the valve passage for mixture in the axis direction. a block-like body having a cylindrical bore with a center of an axis; a valve element having a cylindrical form and rotatably contained in the bore; and a nozzle unit disposed in the valve element along the axis, wherein the valve element includes valve passages for air (20, 22) and a valve passage for mixture extending through the valve element in a direction across the axis, wherein the nozzle unit includes a port which is opened to the valve passage for mixture and ejects fuel, wherein the body includes an upstream body passage (10a, 11 a, 12a) communicating with the valve passages for air (20, 22) and the valve passage for mixture upstream of the valve element, and downstream body passages for air (10b, 12b) and a downstream body passage for mixture (11 b) respectively communicating with the valve passages for air (20, 22) and the valve passage for mixture downstream of the valve element, wherein the valve element is rotatable around the axis between an opened position and an closed position, wherein in the opened position, the valve passages for air (20, 22) and the valve passage for mixture respectively communicate with the downstream body passages for air (10b, 12b) and the downstream body passage for mixture, and the valve passages for air (20, 22) and the valve passage for mixture communicate with the upstream body passage (10a, 11 a, 12a), wherein in the closed position, the valve passages for air (20, 22) and the valve passage for mixture are respectively blocked off from the downstream body passages for air (10b, 12b) and the downstream body passage for mixture, and the valve passages for air (20, 22) and the valve passage for mixture are blocked off from the upstream body passage (10a, 11 a, 12a),wherein the rotary carburetor is a one-bore type rotary carburetor in which the valve passages for air (20, 22) and the valve passage for mixture are partitioned with plate-like valve partitions (24, 25), and the downstream body passages for air (10b, 12b) and the downstream body passage for mixture are partitioned with plate-like body partitions (14b, 15b), wherein two downstream body passages for air (10b, 12b) and two valve passages for air (20, 22) are provided, and are respectively disposed on the opposite sides of the downstream body passage for mixture (11 b) and the valve passage for mixture in the axis direction.