A central mechanism in a tire vulcanizing press including a shaping bladder, a hot pressure supply source, an upper bladder clamp supporting center post, a lower bladder clamp supporting post through which is inserted the center post vertically movably, a mechanism for vertically independently moving both posts, and a latch mechanism for preventing the descent of the support post during vulcanizing press for a tire, the latch mechanism being driven selectively in opening and closing directions relative to the support post by means of a latch opening/closing device, the latch opening/closing device including a drive mechanism capable of moving vertically along a vertical axis, member for converting a vertical linear motion of the drive, a mechanism into a rotational motion around the vertical axis and means for transmitting the thus -obtained rotational motion to the latch mechanism. A lower portion of a housing well which surrounds the support post is closed with two upper and lower partition walls which are interconnected in a vertically spaced relation to each other and the space between the partition walls is filled with a heat insulator, and a cylindrical heat insulating structure which surrounds the housing well is attached to the base side of the vulcanizing press.