A haptic operating device has a base, a stationary central part connected thereto, a rotary knob which can be rotated about the stationary central part and which has a hollow design, and a magnetorheological transmission device for influencing the rotational movement of the rotary knob in a controlled manner. The transmission device has two components which can be rotated relative to each other and one component of which is designed as a brake component that can be rotated relative to the base. The stationary central part is secured to the base by way of a support arm. The transmission device and the support arm are adjacent one another and both are received radially within the rotary knob. The rotary knob is rotationally fixed to the rotatable brake component via a coupling device.