A method of producing a heat-resistant crosslinked fluororubber formed body, including a step (1) of melt-mixing, with respect to 100 mass parts of base rubber containing 40 to 98 mass % of fluororubber and 2 to 40 mass % of ethylene/tetrafluoroethylene copolymer resin, 0.003 to 0.5 mass parts of organic peroxide, 0.5 to 400 mass parts of inorganic filler, 2 to 15 mass parts of a specific silane coupling agent, and silanol condensation catalyst, and including a step (a) of melt-mixing a part of the base rubber, the organic peroxide, the inorganic filler and the silane coupling agent at a temperature equal to or higher than a decomposition temperature of said organic peroxide, and a step (b) of melt-mixing a remainder of the base rubber, and the silanol condensation catalyst, and the fluororubber and the ethylene/tetrafluoroethylene copolymer resin are melt-mixed in any of the steps (a) and (b).