Calibration apparatus for a rotary angle measuring system , with - a shaft holding apparatus which is rotatable about an axis of rotation (D) and which, in a calibration position of the calibration apparatus , can be connected in a rotationally fixed manner to a measuring system shaft of the rotational angle measuring system and which, in a loading position of the calibration apparatus , can be decoupled from the measuring system shaft , - a rotationally stationary housing holding apparatus which, in the calibration position, can be connected in a rotationally fixed manner to a measuring system housing of the rotary angle measuring system and, in the loading position, can be decoupled from the measuring system housing , and - a drive motor for driving the shaft holding apparatus , wherein the shaft holding apparatus comprises at least two clamping jaws (30a-f) which, in the calibration position, can be pressed against a radial outside of the measuring system shaft , wherein the at least two clamping jaws (30a-f) are arranged concentrically with respect to the axis of rotation (D) and can be radially moved collectively, and wherein a clamping jaw actuator is provided which allows a substantially stepless radial movement of the clamping jaws (30a-f), and wherein a coupling module is provided, via which the clamping jaw actuator can be selectively mechanically coupled to the clamping jaws (30a-f) or mechanically decoupled from the clamping jaws (30a-f), and wherein a control unit is provided, by which the drive motor as well as the movement of the clamping jaws (30a-f) can be controlled, and wherein the coupling module can be controlled by the control unit . - a shaft holding apparatus which is rotatable about an axis of rotation (D) and which, in a calibration position of the calibration apparatus , can be connected in a rotationally fixed manner to a measuring system shaft of the rotational angle measuring system and which, in a loading position of the calibration apparatus , can be decoupled from the measuring system shaft , - a rotationally stationary housing holding apparatus which, in the calibration position, can be connected in a rotationally fixed manner to a measuring system housing of the rotary angle measuring system and, in the loading position, can be decoupled from the measuring system housing , and - a drive motor for driving the shaft holding apparatus , wherein the shaft holding apparatus comprises at least two clamping jaws (30a-f) which, in the calibration position, can be pressed against a radial outside of the measuring system shaft , wherein the at least two clamping jaws (30a-f) are arranged concentrically with respect to the axis of rotation (D) and can be radially moved collectively, and wherein a clamping jaw actuator is provided which allows a substantially stepless radial movement of the clamping jaws (30a-f), and wherein a coupling module is provided, via which the clamping jaw actuator can be selectively mechanically coupled to the clamping jaws (30a-f) or mechanically decoupled from the clamping jaws (30a-f), and wherein a control unit is provided, by which the drive motor as well as the movement of the clamping jaws (30a-f) can be controlled, and wherein the coupling module can be controlled by the control unit . <EOS>