A sampling device using force provided by a vacuum chamber (containing air at atmospheric pressure) to suck in a sediment sample. On striking the bottom, the chamber is put into communication with the outside. Water pressure forces the sample into the collecting tube. The pressure chamber itself is a strong brass tube closed at the upper end by a lid and held firmly in position by a clamp. A sampling tube is fixed below the chamber and extends upward into it. Between the upper and lower parts of the central tube is a plug held in position by retaining hooks through slots in the wall of the lower tube. When the device strikes the bottom, a mouth tube rises, disengaging the plug, which flies up the tube. The water then forces material up into the collecting tube.