The disclosure relates a to manufacturing method of an all-solid-state lithium secondary battery including a solid polymer electrolyte, including preparing an all-solid-state lithium secondary battery by interposing a polymer electrolyte between a cathode and an anode; hardening the polymer electrolyte by applying a pressure and heat to the all-solid-state lithium secondary battery; activating the all-solid-state lithium secondary battery by applying a current; and removing a gas generated in the activated all-solid-state lithium secondary battery. By hardening a polymer electrolyte interposed between a cathode and an anode through applying a pressure and heat, a bubble or dead area inside solid polymer electrolyte is minimized with providing an electrode having uniform thickness. By repeating activation operation and removing gas, bonding of electrode stack is more enhanced, and stability of a battery is improved.