A tire vulcanizing device includes a plurality of opening/closing cylinders for respectively independently moving a plurality of mold holding members, which respectively hold a plurality of segmented molds arranged in a circumference direction, forward and backward in radial directions, a plurality of positioning blocks arranged in respective spaces in the circumferential direction between the plurality of segmented molds, respective pairs of engaging members respectively provided at opposite sides of the respective mold holding members, and respective pairs of stopper members each pair of which are provided on the adjoining positioning blocks, for restricting the advanced end positions of the segmented molds in engagements with the respective pairs of engaging members.