A tire manufacturing method in which a sealing layer is formed of a strip-like sealant on an inner surface of a tire; wherein a pair of side surfaces of the sealant located on both sides in a width direction of the sealant is inclined toward the same side in the width direction of the sealant with respect to a thickness direction of the sealant, and the sealant is spirally arranged on the inner surface of the tire with the adjacent side surfaces of the sealant being overlapped with each other, wherein the tire manufacturing method comprises the steps of: placing the tire in a rotating device, placing a nozzle in the tire by a moving device, rotating the tire by the rotating device so as to relatively move the nozzle along the tire circumferential direction, gradually moving the nozzle in the tire width direction by the moving device, the nozzle facing to the inner surface of the tire, and at the same time, supplying sealant to the nozzle by a supply device and discharging the sealant from a discharging port of the nozzle towards the inner surface of the tire, the strip-like sealant being formed into a predetermined cross-sectional shape by the discharging port of the nozzle, and wherein the pair of side surfaces of the sealant is inclined at an angle of not less than 5° and not more than 15° toward the same side in the width direction of the sealant with respect to the thickness direction of the sealant. a pair of side surfaces of the sealant located on both sides in a width direction of the sealant is inclined toward the same side in the width direction of the sealant with respect to a thickness direction of the sealant, and the sealant is spirally arranged on the inner surface of the tire with the adjacent side surfaces of the sealant being overlapped with each other, wherein the tire manufacturing method comprises the steps of: placing the tire in a rotating device, placing a nozzle in the tire by a moving device, rotating the tire by the rotating device so as to relatively move the nozzle along the tire circumferential direction, gradually moving the nozzle in the tire width direction by the moving device, the nozzle facing to the inner surface of the tire, and at the same time, supplying sealant to the nozzle by a supply device and discharging the sealant from a discharging port of the nozzle towards the inner surface of the tire, the strip-like sealant being formed into a predetermined cross-sectional shape by the discharging port of the nozzle, and wherein the pair of side surfaces of the sealant is inclined at an angle of not less than 5° and not more than 15° toward the same side in the width direction of the sealant with respect to the thickness direction of the sealant. placing the tire in a rotating device, placing a nozzle in the tire by a moving device, rotating the tire by the rotating device so as to relatively move the nozzle along the tire circumferential direction, gradually moving the nozzle in the tire width direction by the moving device, the nozzle facing to the inner surface of the tire, and at the same time, supplying sealant to the nozzle by a supply device and discharging the sealant from a discharging port of the nozzle towards the inner surface of the tire, the strip-like sealant being formed into a predetermined cross-sectional shape by the discharging port of the nozzle, and wherein the pair of side surfaces of the sealant is inclined at an angle of not less than 5° and not more than 15° toward the same side in the width direction of the sealant with respect to the thickness direction of the sealant.