A tire vulcanizing mold comprising: a sidewall ring for molding a sidewall portion of a tire, the sidewall ring comprising a main body extending continuously in the circumferential direction thereof, and a plurality of mold pieces mounted on the main body, wherein the main body is provided with a first molding surface for molding a part of the outer surface of the sidewall portion, a circumferentially extending groove recessed from the first molding surface and extending in the circumferential direction, and exhaust flow paths extending from the circumferentially extending groove to an outside of the main body, wherein each of the mold pieces has a second molding surface for molding a part of the outer surface of the sidewall portion, and wherein the mold pieces are mounted in the circumferentially extending groove so as to be adjacent to each other in the circumferential direction, and micro-gaps for discharging gas existing in the tire vulcanizing mold are formed between the mold pieces, and/or between the main body and the mold pieces so as to communicate with the exhaust flow paths, wherein the micro-gaps include a first micro-gap formed between the main body and a first peripheral surface of each mold piece which surface is on the radially inside or radially outside of the above-said each mold piece, and wherein said first peripheral surface is provided with a first shallow groove for forming the first micro-gap to extend between the second molding surface and a bottom surface of the circumferentially extending groove. a sidewall ring for molding a sidewall portion of a tire, the sidewall ring comprising a main body extending continuously in the circumferential direction thereof, and a plurality of mold pieces mounted on the main body, wherein the main body is provided with a first molding surface for molding a part of the outer surface of the sidewall portion, a circumferentially extending groove recessed from the first molding surface and extending in the circumferential direction, and exhaust flow paths extending from the circumferentially extending groove to an outside of the main body, wherein each of the mold pieces has a second molding surface for molding a part of the outer surface of the sidewall portion, and wherein the mold pieces are mounted in the circumferentially extending groove so as to be adjacent to each other in the circumferential direction, and micro-gaps for discharging gas existing in the tire vulcanizing mold are formed between the mold pieces, and/or between the main body and the mold pieces so as to communicate with the exhaust flow paths, wherein the micro-gaps include a first micro-gap formed between the main body and a first peripheral surface of each mold piece which surface is on the radially inside or radially outside of the above-said each mold piece, and wherein said first peripheral surface is provided with a first shallow groove for forming the first micro-gap to extend between the second molding surface and a bottom surface of the circumferentially extending groove. a main body extending continuously in the circumferential direction thereof, and a plurality of mold pieces mounted on the main body, wherein the main body is provided with a first molding surface for molding a part of the outer surface of the sidewall portion, a circumferentially extending groove recessed from the first molding surface and extending in the circumferential direction, and exhaust flow paths extending from the circumferentially extending groove to an outside of the main body, a first molding surface for molding a part of the outer surface of the sidewall portion, a circumferentially extending groove recessed from the first molding surface and extending in the circumferential direction, and exhaust flow paths extending from the circumferentially extending groove to an outside of the main body, wherein each of the mold pieces has a second molding surface for molding a part of the outer surface of the sidewall portion, and wherein the mold pieces are mounted in the circumferentially extending groove so as to be adjacent to each other in the circumferential direction, and micro-gaps for discharging gas existing in the tire vulcanizing mold are formed between the mold pieces, and/or between the main body and the mold pieces so as to communicate with the exhaust flow paths, wherein the micro-gaps include a first micro-gap formed between the main body and a first peripheral surface of each mold piece which surface is on the radially inside or radially outside of the above-said each mold piece, and wherein said first peripheral surface is provided with a first shallow groove for forming the first micro-gap to extend between the second molding surface and a bottom surface of the circumferentially extending groove.