Dismounting machine for dismounting a tyre from a rim, comprising a supporting base frame that is provided with: - a vertical carrying body for a rim, wherein said carrying body is connected to the base frame, is rotatable by a motor relative to the base frame about a rotation axis that extends in a vertical direction, and is provided with fastening means for fastening a rim in a fixed position on an upper side of the carrying body, so that a principal axis of the rim thus fixed extends in a direction that coincides with the central rotation axis of the carrying body, so that rotation of the carrying body leads to rotation of the fixed rim about the principal axis, - a vertical column connected rigidly to the base frame, which is located at a distance from the carrying body, said column being provided with a guide arm and an auxiliary arm, which extend from the column in the direction of the carrying body, and which, movable independently of one another, are connected to the column, so that the guide arm and the auxiliary arm can be placed independently of one another in a working position as separate tools for dismounting a tyre from a rim fixed on the carrying body, wherein the column is provided with a motor-driven adjusting mechanism for adjusting the height of the guide arm on the column, and the guide arm is provided at a distal end with a guide head with a guiding surface that is designed for guiding an inner edge of a tyre over an outer edge of the rim when the guide arm is in its working position between the outer edge of the rim and the inner edge of the tyre, characterized in that the auxiliary arm is connected swivelling with a proximal end to the column, and a distal end is provided with a hook arm, a distal end of which is connected to a hook, said hook being designed to grip behind an inner edge of a tyre when the auxiliary arm is put in its working position, wherein the hook arm comprises a motor-driven hook mechanism for moving the hook in a vertical direction for moving an inner edge of a tyre over an outer edge of the rim when the auxiliary arm is put in its working position, and wherein the auxiliary arm is connected to the column, swivelling in such a way that the hook can follow a circular path round the rotation axis of the carrying body. - a vertical carrying body for a rim, wherein said carrying body is connected to the base frame, is rotatable by a motor relative to the base frame about a rotation axis that extends in a vertical direction, and is provided with fastening means for fastening a rim in a fixed position on an upper side of the carrying body, so that a principal axis of the rim thus fixed extends in a direction that coincides with the central rotation axis of the carrying body, so that rotation of the carrying body leads to rotation of the fixed rim about the principal axis, - a vertical column connected rigidly to the base frame, which is located at a distance from the carrying body, said column being provided with a guide arm and an auxiliary arm, which extend from the column in the direction of the carrying body, and which, movable independently of one another, are connected to the column, so that the guide arm and the auxiliary arm can be placed independently of one another in a working position as separate tools for dismounting a tyre from a rim fixed on the carrying body, wherein the column is provided with a motor-driven adjusting mechanism for adjusting the height of the guide arm on the column, and the guide arm is provided at a distal end with a guide head with a guiding surface that is designed for guiding an inner edge of a tyre over an outer edge of the rim when the guide arm is in its working position between the outer edge of the rim and the inner edge of the tyre, characterized in that the auxiliary arm is connected swivelling with a proximal end to the column, and a distal end is provided with a hook arm, a distal end of which is connected to a hook, said hook being designed to grip behind an inner edge of a tyre when the auxiliary arm is put in its working position, wherein the hook arm comprises a motor-driven hook mechanism for moving the hook in a vertical direction for moving an inner edge of a tyre over an outer edge of the rim when the auxiliary arm is put in its working position, and wherein the auxiliary arm is connected to the column, swivelling in such a way that the hook can follow a circular path round the rotation axis of the carrying body.