To provide a method of manufacturing an ion-conducting solid electrolyte using a green sheet having mechanical characteristics such that the sheet can sufficiently endure a variety of mechanical stresses during a manufacturing process.

Using a ceramic green sheet that can endure mechanical stresses in a detachment process for a carrier film, a lamination process for the green sheet or the like by adjusting a percentage of water of the ceramic green sheet after a drying process and/or an environment under which the ceramic green sheet is disposed, an ion-conducting solid electrolyte is manufactured. In this way, it is possible to effectively prevent occurrence of defects within the green sheet in transportation, carrier film detachment or a lamination process.