A separator for an electrochemical device comprising a porous polymer substrate, and a porous coating layer on at least one surface of the porous polymer substrate. The porous coating layer comprises inorganic particles and an ion conducting polymer. The ion conducting polymer comprises a fluorine-based copolymer comprising fluoroolefin-based segments with anionic functional groups present in side chains or terminals, and an electrochemical device comprising the same. It is possible to provide a separator with high ionic conductivity and an increased peel strength between the porous polymer substrate and the porous coating layer, and an electrochemical device with improved properties.