Abstract: A degassing apparatus which has a degassing head from which extends a tube; a shaft is rotated in the tube; a screw conveyor above intake holes of the tube conveys drill mud upward against a deflector disc at the open top of the tube; three rows of inwardly inclined baffles around the side wall of the degassing head are so arranged that the baffles of the various rows are staggered relatively to one another; the mud flows by gravity to the inclined bottom of the head and to an outlet leading out of the head to a container for the degassed mud; a fan above the deflector disc sucks air through the mud spray and out through an outlet; a conduit conducts gas from below the mud spray to the fan and a vent; the shaft at the bottom of the tube is held in a bearing protected against influx of mud; adjustable legs on the degasser head are adapted to support the head on top of a vessel in which the drill mud is contained.