The present invention relates to a shifting device for a transmission unit of a vehicle, in particular a vehicle that is driven by muscle force. The transmission unit has a first shaft, which is formed as a hollow shaft, on which a plurality of free gears is mounted. The free gears are in engagement with a corresponding plurality of gearwheels, which are mounted on a second shaft, wherein the free gears are connectable to the first shaft by means of selecting devices. The selecting devices can be actuated by means of a camshaft arranged coaxially in the first shaft, wherein the camshaft is connected to a driving device in order to be rotated relative to the first shaft to actuate the selecting means.