ALL-SOLID-STATE LITHIUM ION SECONDARY BATTERY

Disclosed is an all-solid-state lithium ion secondary battery being excellent in cycle characteristics. The all-solid-state lithium ion secondary battery may be an all-solid-state lithium ion secondary battery, wherein an anode comprises an anode active material, an electroconductive material and a solid electrolyte; wherein the anode active material comprises at least one active material selected from the group consisting of a metal that is able to form an alloy with Li, an oxide of the metal, and an alloy of the metal and Li; and wherein a bulk density of the solid electrolyte is 0.3 g/cmor more and 0.6 g/cmor less.