An improved tire loading mechanism of a tire cooler in a tire vulcanizing machine is proposed to save time and human labor, to prevent jamming of a screw portion and to enhance economy of the machine. The tire loading mechanism is composed of a main shaft pivotably supported from a rotary table and rotationally driven by a drive source, an outer cylinder mounted to the main shaft so as to be relatively displaceable in an axial direction via screw threads and having an upper bead ring support flange at its lower end, and a housing mounted to the lower end of the main shaft via disengageably fitting claws and having a lower bead ring support flange at its upper end. A disengageable fitting rod for stopping rotation of the outer cylinder is provided on the rotary table at a position opposed to a vertical groove on the surface of the outer cylinder. An arrangement provided between the main shaft and the outer cylinder fixedly secures the outer cylinder to the main shaft upon rotational air cooling of the tire. Such arrangement essentially includes an elastic ring on the outer circumference of the main shaft which is pneumatically expanded to be pressed against the inner circumference of the outer cylinder.