Abstract: The gravity separator is intended for use in dental suction apparatus comprising at least one sucker having a suction mouthpiece and a sucker line. The suction apparatus comprises also a suction-producing machine including a pump for generating a vacuum in a suction line. The separator comprises at least two collecting containers, which are adapted to be connected in series to the at least one sucker line connected to one or more suction mouthpieces and are detachably connected to respective hollow head pieces, one of which has an inlet for connection to said at least one sucker line whereas another head piece is adapted to be connected to a suction line leading to the suction-generating machine, particularly to a pump. Each container has an open mouth leading to the associated head piece. A suction pipe extends into each container. That suction pipe which extends into the last container is connected to the suction line leading to the pump.