Abstract: An assembled unit for collecting solid substance is provided for quickly and accurately collecting the solid substance in a liquid sample. The liquid sample introduced with suction is separated according to solid-liquid separation by the filter means 2 and the solid substance so separated is kept hermetically in the filter means 2. The solid substances are collected by applying pneumatic pressure from the inner side of the unit toward the filter matrix 3 and drifting the solid substances from the conduit 4, wherein the press means 13 is inserted into the support member 14 connected to the filter means 2.