To make realizable a relatively low pressure loss even if a sufficient amt. of a dehalogenated type fire retardant poor in fire retardancy is bonded.

The fire retardant filter 10 is obtained by applying a fire retardant 2 to one surface of a filter material 1 in a predetermined pattern by printing technique. The filter material 1 comprises a cloth which is based on at least one kind of a fiber composed of a polymer selected from polyester, polypropylene and polyacrylonitrile and contains 10-90 mass % of a fiber having no m.p., for example, rayon, cotton, acetate, melamine, novoloid (phenolic fiber) or carbon fiber. As the fire retardant 2, a phosphate fire retardant or an inorg. fire retardant being a fire retardant not using a substance containing halogen (chlorine or bromine) is used.