A film is made of an insulating matrix resin and an electroconductive material, in which the electroconductive material is dispersed in the insulating matrix resin in such a manner that a surface resistivity of A [&OHgr;] of the film and a volume resistivity of B [&OHgr;·cm] of the film in the direction of a thickness thereof normal to the surface of the film satisfy a relationship of: A>B, and when the film has a thickness of T [cm], the electroconductive material is dispersed in the insulating matrix resin in such a manner that the surface resistivity of A [&OHgr;] of the film and the volume resistivity of B [&OHgr;·cm] of the film satisfy a relationship of; A[&OHgr;]'T [cm]>B [&OHgr;·cm]. This film can be prepared by a centrifugal molding method.