A tire vulcanizing method for vulcanizing a green tire using a vulcanization mold including a tread mold for molding a tread portion of the green tire and a pair of side molds for molding a pair of sidewall portions of the green tire , the tire vulcanizing method comprising: a mounting step (S1) of mounting the green tire within the vulcanization mold in a state where the vulcanization mold is opened; and a vulcanizing step (S2) of vulcanizing the green tire in a closed state where the tread mold and the pair of side molds are set at predetermined reference positions (P), wherein the mounting step (S1) includes a green tire pressing step (S1c) of, after the green tire is mounted within the vulcanization mold , moving at least one of the pair of side molds such that the pair of side molds are closer to each other in a tire axial direction than the reference positions (P) thereof, to reduce a width in the tire axial direction between the pair of sidewall portions of the green tire , and a positioning step (S1d) of, after a predetermined time elapses from the green tire pressing step (S1c), moving the pair of side molds to the reference positions (P) and stopping the pair of side molds , characterized in that the tire vulcanizing method comprises a tread mold moving step (S1e) of, after the positioning step (S1d), moving the tread mold in a tire radial direction to position the tread mold at the reference position (P) thereof, and a division position (Q) between the pair of side molds and the tread mold is within 15% of a tire cross-sectional height (H) inward and outward in the tire radial direction from a maximum width position (M) of a vulcanized tire . a mounting step (S1) of mounting the green tire within the vulcanization mold in a state where the vulcanization mold is opened; and a vulcanizing step (S2) of vulcanizing the green tire in a closed state where the tread mold and the pair of side molds are set at predetermined reference positions (P), wherein the mounting step (S1) includes a green tire pressing step (S1c) of, after the green tire is mounted within the vulcanization mold , moving at least one of the pair of side molds such that the pair of side molds are closer to each other in a tire axial direction than the reference positions (P) thereof, to reduce a width in the tire axial direction between the pair of sidewall portions of the green tire , and a positioning step (S1d) of, after a predetermined time elapses from the green tire pressing step (S1c), moving the pair of side molds to the reference positions (P) and stopping the pair of side molds , a green tire pressing step (S1c) of, after the green tire is mounted within the vulcanization mold , moving at least one of the pair of side molds such that the pair of side molds are closer to each other in a tire axial direction than the reference positions (P) thereof, to reduce a width in the tire axial direction between the pair of sidewall portions of the green tire , and a positioning step (S1d) of, after a predetermined time elapses from the green tire pressing step (S1c), moving the pair of side molds to the reference positions (P) and stopping the pair of side molds , characterized in that the tire vulcanizing method comprises a tread mold moving step (S1e) of, after the positioning step (S1d), moving the tread mold in a tire radial direction to position the tread mold at the reference position (P) thereof, and a division position (Q) between the pair of side molds and the tread mold is within 15% of a tire cross-sectional height (H) inward and outward in the tire radial direction from a maximum width position (M) of a vulcanized tire . <EOS>