It is an object to provide a high ion conductive solid electrolyte which uses organic and inorganic complex compound having water absorption and water resistance and to provide an electrochemical system using the high ion conductive solid electrolyte. The high ion conductive solid electrolyte is composed a complex compound including water that has zirconic acid compound and polyvinyl alcohol and compound having carboxyl group or metal salt of the compound having carboxyl group. An aqueous solution in which zirconium salt or oxyzirconnium salt and polyvinyl alcohol and compound having carboxyl group or metal salt of the compound having carboxyl group are dissolved is neutralized by alkali. After removing water used as solvent, unnecessary salts are removed from the neutralized solution. The high ion conductive solid electrolyte is obtained which is composed of the complex compound. Various electrochemical systems are obtained each of which use the high ion conductive solid electrolyte.