An air leading type two-stroke engine (110, 112, 114) that, at an initial stage of a scavenging process of the engine, induces air charged in a scavenging channel of an engine body into a combustion chamber thereof and then induces an air-fuel mixture inside a crankcase of the engine body into the combustion chamber through the scavenging channel, the two-stroke engine (110, 112, 114) comprising: a first passage (40, 54) extending from a filter element of an air cleaner to the engine body and allowing air to be supplied to the scavenging channel; a second passage (42, 56) extending from the filter element to the engine body and allowing at least air to be supplied to the crankcase; a carburetor having an air channel being part of the first passage (40,54) and an air-fuel mixture channel being part of the second passage (42,56); a communication portion (44, 208, 294, 306, 314) located inside the carburetor (210, 212, 216, 230, 236, 240, 246, 254, 260, 268, 274, 290, 296, 300, 310), or between the carburetor (210, 212, 216, 230, 236, 240, 246, 254, 260, 268, 274, 290, 296, 300, 310) and the filter element of the air cleaner, or between the carburetor (210, 212, 216, 230, 236, 240, 246, 254, 260, 268, 274, 290, 296, 300, 310) and the engine body for bringing the first passage (40, 54) and the second passage (42, 56) into communication with each other; and an inhibition member (16, 202, 214, 218, 232, 238, 242, 248, 256, 262,270, 276, 292b, 298, 304, 312) placed in or in the vicinity of the communication portion (44, 208, 294, 306, 314) for inhibiting entry of a blow-back flow of the air-fuel mixture from the second passage (42, 56) into the first passage (40, 54) through the communication portion while permitting a part of a blow-back flow of the air to enter from the first passage (40, 54) into the second passage (42, 56) through the communication portion, and wherein the inhibition member (16, 202, 214, 218, 232, 238, 242, 248, 256, 262,270, 276, 292b, 298, 304, 312) guides the blow-back flow of the air towards an opening of the communication portion communicating the first passage (12, 40, 54) with the second passage (14, 42, 56). a first passage (40, 54) extending from a filter element of an air cleaner to the engine body and allowing air to be supplied to the scavenging channel; a second passage (42, 56) extending from the filter element to the engine body and allowing at least air to be supplied to the crankcase; a carburetor having an air channel being part of the first passage (40,54) and an air-fuel mixture channel being part of the second passage (42,56); a communication portion (44, 208, 294, 306, 314) located inside the carburetor (210, 212, 216, 230, 236, 240, 246, 254, 260, 268, 274, 290, 296, 300, 310), or between the carburetor (210, 212, 216, 230, 236, 240, 246, 254, 260, 268, 274, 290, 296, 300, 310) and the filter element of the air cleaner, or between the carburetor (210, 212, 216, 230, 236, 240, 246, 254, 260, 268, 274, 290, 296, 300, 310) and the engine body for bringing the first passage (40, 54) and the second passage (42, 56) into communication with each other; and an inhibition member (16, 202, 214, 218, 232, 238, 242, 248, 256, 262,270, 276, 292b, 298, 304, 312) placed in or in the vicinity of the communication portion (44, 208, 294, 306, 314) for inhibiting entry of a blow-back flow of the air-fuel mixture from the second passage (42, 56) into the first passage (40, 54) through the communication portion while permitting a part of a blow-back flow of the air to enter from the first passage (40, 54) into the second passage (42, 56) through the communication portion, and wherein the inhibition member (16, 202, 214, 218, 232, 238, 242, 248, 256, 262,270, 276, 292b, 298, 304, 312) guides the blow-back flow of the air towards an opening of the communication portion communicating the first passage (12, 40, 54) with the second passage (14, 42, 56).