To provide a lithium secondary battery capable of improving input and output characteristics.

An electrode group 6 is stored inside a battery container 7 in the lithium secondary battery 20. A positive electrode plate and a negative electrode plate are wound via a separator W5 regarding the electrode group 6. A positive electrode mixture layer W2 including lithium containing double oxide as a positive electrode active material is formed on both surfaces of an aluminum foil W1 in the positive electrode plate. A negative electrode mixture layer W4 including graphite as a negative electrode active material is formed on both surfaces of a copper foil W3 in the negative electrode plate. A nonaqueous electrolyte which soaks the whole electrode group 6 is poured into the battery container 7. What 6-fluorophosphoric acid lithium is dissolved in a mixed organic solvent of EC, DEC, and DMC is used as a nonaqueous electrolyte. Polyoxazoline chain contained polymer is mixed in the nonaqueous electrolyte. Thus, wettability of the positive and negative electrode plates and the separator to the nonaqueous electrolyte is improved.