The operating device (1) has two belt parts (6,9) that fit around the rim or spoke of a steering wheel and are joined together. One belt part has a clamp lever (3) to pivot in a position that clamps the belt parts together. The clamp lever has a pivot axis (4) on the operation device. One belt part is connected to a parallel axis (5) of the clamp lever. The clamp level pivots between a clamped position where the axis is close to the operation unit and a free position, where the axis is spaced from the operation unit.
