The invention enables an adequate crankcase negative pressure in an internal combustion engine, in all operating ranges to the extent possible and using a suction device for the crankcase ventilation of an internal combustion engine, which suction device is equipped with a housing, a controllable electric motor and a compressor for conveying crankcase gas, which compressor is driven by the electric motor, the compressor having connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor.