PURPOSE: To securely demount a tire from a wheel rim by constituting a tire demounting device in such a way that turn in the tire demounting direction of an operation lever is prevented after a tire bead holder moves in the radial direction by a predetermined amount due to the turn thereof and is changed to a travel in the axial direction.

CONSTITUTION: When an operation lever 2 is turned, a claw 13 of a tire bead holder 12 is engaged with a bead 15' due to bias force of a compression spring 18 and turns in the clockwise direction around a pivot axis 11 for the operation lever 2. The pivot axis 11 continues to travel on a circular arc locus around a pivot axis 22. Consequently, the claw 13 pulls a bead part 15' to the radial direction to separate the bead part 15' from a rim fringe 8. When a hinge pin 19 of the tire bead holder 12 comes into contact with a screw 20 through a stop tube 21, the turn around the axis 11 stops. Accordingly, the claw 13 moves in the axial direction accompanied by the bead 15' due to the turn of the operation lever 2 after that to pass the rim fringe 8. In this way, tire demounting can be done securely.