A fluoride-based resin prepreg and a circuit substrate using the same are provided. The fluoride-based resin prepreg includes 100 PHR of a fluoride-based resin and 20 to 110 PHR of an inorganic filler. Based on a total weight of the fluoride-based resin, the fluoride-based resin includes 10 to 80 wt % of polytetrafluoroethylene (PTFE), 10 to 50 wt % of fluorinated ethylene propylene (FEP), and 0.1 to 40 wt % of perfluoroalkoxy alkane (PFA). The circuit substrate includes a fluoride-based resin substrate and a circuit layer that is formed on the fluoride-based resin substrate.