Abstract: The present invention relates to a tank ventilation device (1) for a motor vehicle, with at least one storage device (2) for storing hydrocarbon gas, the tank connection (9) of which is connected via a ventilation line (12) to a fuel tank (5) of a vehicle, the engine connection (10) of which is connected via a regeneration line (13) to a fresh gas system (6) of an internal combustion engine (4) of the vehicle, and the environment connection (11) of which communicates via an environment line (15) with the environment (7) of the vehicle. In order to reduce hydrocarbon emissions, at least one conversion device (3) can be provided, which is used for materially converting hydrocarbon gas and is connected directly or indirectly to the fuel tank (5) via a feed line (18) on the input side.