of wollastonite as inorganic fibers is applied to the inner surface of the base material 2 where an adhesive has been applied beforehand and then calcining is performed that is the inner surface of the ring structure which is previously subjected to ground treatment by blasting or the like is washed with alcohol or the like and a thermosetting adhesive such as a phenolic resin and an epoxy resin is applied to the inner surface subsequently the ring structure is placed in a thermostatic chamber or the like and kept under an atmosphere of 70 to 120 u00b0 c for 10 to 30 minutes so that the adhesive is dried the ring structure is set into a lower die of molding dies thereafter the friction material is introduced and packed into the cavity formed between the inner surface of the ring structure and the outer surface of a core using a conventional oil hydraulic press machine or the like the friction material is compressed by means of a punch of an upper die to be pre molded at a die temperature within the range from normal temperature to 50 u00b0 c the molding dies are then placed on a heating platen preset at 180 to 300 u00b0 c in a conventional straight hydraulic molding machine and the material is calcined heated and press molded for 5 to 30 minutes to form a friction material layer integrated with the ring structure the calcined friction material is further machined as shown in the cross sectional view of fig3 the taper angle of the sliding surface to the axis is set at 7 u00b0 u03b8 herein u03b8 is the relative taper angle between the friction material.