A method comprising at least a step of preparing a silane master batch by melt-kneading a base resin (RB) containing a non-aromatic organic oil, an organic peroxide, an inorganic filler, and a silane coupling agent, in specific mass ratio, and a step of mixing the silane master batch and a silanol condensation catalyst or a silane master batch; a heat-resistant silane crosslinked resin molded body and a heat-resistant silane crosslinkable resin composition prepared by the method, and a silane master batch and a heat-resistant product.