To provide a thermoforming method of a friction material capable of efficiently discharging the gas formed during thermoforming, and a mold for molding the friction material used therein.

The thermoforming mold comprises a frame mold 6 having a piercing hollow part 6a, the press mold 5 arranged on one side of the hollow part and the receiving mold 7 arranged on the other side of the hollow mold and is constituted so that at least one of the press mold 5 and the receiving mold 7 is freely slid in the hollow part 6a of the frame mold 6. This thermoforming mold is used to charge a raw material of the friction material in the frame mold 6 and pressure is applied to the friction material by the press mold 5 and the receiving mold 7 to heat and mold the raw material. The frame mold 6 is divided into a plurality of parts and the pressure applied during thermoforming by the press mold and the receiving mold is reduced while a plurality of the divided frame molds are separated to discharge the gas formed during thermoforming from the gap between the separated frame molds.