PURPOSE: To inexpensively produce a filter capable of filtering out minute dust, etc., capable of maintaining high filtering performance for a long time and having high strength.

CONSTITUTION: Plural wire net layers 2-6 each consisting of plural wire nets and different from each other in mesh are superposed, flatly compacted and sintered. Since the resulting filter 1 is made thick as a whole, it can filter out even minute dust, etc. By the presence of the large-mesh wire nets 3, 5 each composed of thick wires, the filter 1 can maintain high strength. Since dust is dispersed in the filter 1 by the presence of the large-mesh wire net layers 3, 5, the filter 1 hardly causes blocking and can maintain high filtering performance for a long time.