PURPOSE: To provide a filtering cylinder made of an easily available construction material, possible of industrial production and having high durability, by forming an aggregate into a spirally cylindrical shape having the prescribed pitch and diameter, and inserting fibers densely between the aggregates.

CONSTITUTION: An aggregate 1 made of a thermoplastic synthetic resin is formed into a spirally cylindrical shape, and fibrous filter medium 2 is inserted densely between the aggregates 1 to form a filtering cylinder 3. The aggregate 1 has a Z-shaped cross section, and a fluid is passed through gaps formed between adjoining aggregates 1 and 1. Further, both of activated carbon and silica gel are distributed in the filter medium 2. One open end of the filtering cylinder 3 formed by said procedure is closed by a plug-plate 5, and a sirocco fan is attached to the other open end of the cylinder 3, which is installed in a room. When the fan 6 is driven to exhaust the air in the cylinder to the outside, the air in the room is passed through the gaps between the aggregates and the fibrous filter medium 2. Thus, a deodorizing and adsorbing effect is obtained.