A tire mounting machine comprising: a tire holding device (50, 80) including vertically oriented card-shaped chucking paddles (60, 90) arranged in side-by-side disposition to be included in an imaginary circular cylinder with a circumferential spacing between adjoining chucking paddles (60, 90), in such a manner that the card-shaped chucking paddles (60, 90) are concurrently movable radially outward and inward to increase and decrease a diameter of the imaginary circular cylinder, the tire holding device (50, 80) being adapted to hold a green tire from inside the tire positioned around the tire holding device (50, 80, when the diameter thereof is increased; and a bladder device provided with a tubular upright vulcanization bladder to be positioned in a center of a vulcanization-mold and adapted to be inflated by supply of a shaping gas thereinto, the tubular vulcanization bladder having a lower opening held and closed by a lower clamp ring and an upper opening held and closed by an upper clamp ring, the upper opening of the vulcanization bladder being movable vertically in a region above the lower clamp ring; wherein the tire holding device (50, 80) is operable to hold a bead section (Tb) of the green tire by means of the chucking paddles (60, 90) and to carry the thus held green tire around the upright vulcanization bladder, while the bladder device is operable to inflate the vulcanization bladder by supplying the shaping gas into the vulcanization bladder concurrently with lowering of the upper clamp ring, thereby to cause the vulcanization bladder to be pressed against an internal surface of the green tire for setting the green tire in the vulcanization-mold: characterized in that: each of the chucking paddles (60, 90) has, on a lower portion thereof, guide extensions (65a, 65b, 95a, 95b) on two lateral sides thereof extending in circumferential directions; and the chucking paddles (60, 90) have their guide extensions (65a, 65b, 95a, 95b) protruding to reach the guide extensions of circumferentially adjoining chucking paddles (60, 90) in mutually and constantly overlapping disposition. a tire holding device (50, 80) including vertically oriented card-shaped chucking paddles (60, 90) arranged in side-by-side disposition to be included in an imaginary circular cylinder with a circumferential spacing between adjoining chucking paddles (60, 90), in such a manner that the card-shaped chucking paddles (60, 90) are concurrently movable radially outward and inward to increase and decrease a diameter of the imaginary circular cylinder, the tire holding device (50, 80) being adapted to hold a green tire from inside the tire positioned around the tire holding device (50, 80, when the diameter thereof is increased; and a bladder device provided with a tubular upright vulcanization bladder to be positioned in a center of a vulcanization-mold and adapted to be inflated by supply of a shaping gas thereinto, the tubular vulcanization bladder having a lower opening held and closed by a lower clamp ring and an upper opening held and closed by an upper clamp ring, the upper opening of the vulcanization bladder being movable vertically in a region above the lower clamp ring; wherein the tire holding device (50, 80) is operable to hold a bead section (Tb) of the green tire by means of the chucking paddles (60, 90) and to carry the thus held green tire around the upright vulcanization bladder, while the bladder device is operable to inflate the vulcanization bladder by supplying the shaping gas into the vulcanization bladder concurrently with lowering of the upper clamp ring, thereby to cause the vulcanization bladder to be pressed against an internal surface of the green tire for setting the green tire in the vulcanization-mold: characterized in that: each of the chucking paddles (60, 90) has, on a lower portion thereof, guide extensions (65a, 65b, 95a, 95b) on two lateral sides thereof extending in circumferential directions; and the chucking paddles (60, 90) have their guide extensions (65a, 65b, 95a, 95b) protruding to reach the guide extensions of circumferentially adjoining chucking paddles (60, 90) in mutually and constantly overlapping disposition. each of the chucking paddles (60, 90) has, on a lower portion thereof, guide extensions (65a, 65b, 95a, 95b) on two lateral sides thereof extending in circumferential directions; and the chucking paddles (60, 90) have their guide extensions (65a, 65b, 95a, 95b) protruding to reach the guide extensions of circumferentially adjoining chucking paddles (60, 90) in mutually and constantly overlapping disposition.