In the case of a device for ascertaining a fill level of a medium inside a collection container, having at least one measuring chamber, in which an ultrasonic sensor is arranged, connected to conduct media to the collection chamber, and having at least one antechamber connected upstream from the measuring chamber, which has at least one inlet opening for the medium from the collection chamber, at least one flow damper for the medium, according to the invention, is arranged in at least one subarea of the antechamber. Thereby multiple antechambers, which are connected in series one behind another to conduct media, are connected upstream from the measuring chamber.