PROBLEM TO BE SOLVED: To provide a tire fixation mechanism which can securely fix even a hard tire in such a manner that the rotation center of the tire is shifted, and a tire changer using the tire fixation mechanism.SOLUTION: On a base upper surface of a tyre changer, a pivot 30 which has a tapered part 32 on a tip side thereof is projected, and a projection member 34 having plural grooves 36 on the outer peripheral surface thereof is projected from the tip. The lower end side of the projection member 34 is energized upwards by a spring 44 which is provided in the pivot 30. A connection member 50, which is detachable from a wheel 70, comprises a flange part 52 and a cylindrical part 56, and a hollow part 60 of the cylindrical part 56 is provided with a tapered part 62A and plural grooves 66. The grooves 36, 66 are engaged with each other with use of the tapered parts 32, 62A and the spring 44 and are fixed from above by a stopper 88. A tool 190 supported on the base via a support mechanism is so supported that the tool keeps a predetermined attitude by two links rotating on a tool holder side as a fulcrum.