A liquid fluoropolyether base rubber composition comprising (A) a linear fluoropolyether compound containing at least two alkenyl groups and having a perfluoroalkyl ether structure in its backbone, (B) a silica filler having a specific surface area of at least 100 m2/g and a bulk density of 100-200 g/l, (C) a curing amount of an organosilicon compound having at least two silicon-bound hydrogen atoms, and (D) a hydrosilylation catalyst is unlikely to thicken despite filler loading, is suitable for liquid injection molding and curable into products having improved mechanical properties as well as water repellency, oil repellency, solvent resistance, chemical resistance and weather resistance.