There are provided a solvent for dissolving an electrolyte salt of lithium secondary battery comprising at least one fluorine-containing solvent (I) selected from the group consisting of a fluorine-containing ether, a fluorine-containing ester and fluorine-containing chain carbonate, 1,2-dialkyl-1,2-difluoroethylene carbonate (II) and other carbonate (III), a non-aqueous electrolytic solution comprising the solvent and an electrolyte salt, and a lithium secondary battery using the non-aqueous electrolytic solution. The solvent for dissolving an electrolyte salt provides a lithium secondary battery being excellent particularly in discharge capacity, rate characteristic and cycle characteristic and has enhanced incombustibility (safety) and the non-aqueous electrolytic solution comprises the solvent and an electrolyte salt.