An auxiliary contact block is disclosed for expanding a switching device and to a switching device having at least one auxiliary contact block. A compact auxiliary contact block, i.e. a block requiring little wiring and space, for a switching device is disclosed, and a switching device having at least one auxiliary contact block. In at least one embodiment of the auxiliary contact block, the auxiliary contact block includes auxiliary contacts disposed in a plane, the contacts having contact bridges and associated fixed contact pieces, and at least one contact slider, which can be equipped with at least one auxiliary contact pair. The configuration of the auxiliary contacts in a plane as described herein allows a very small installation size and very little wiring complexity of the auxiliary contacts in a simple manner. The actuating unit can, for example, be configured as a slider that couples the contact slider and the switching device with each other.