Among the problems on the electrode/solid electrolyte interface, we focused on the lithium concentration chage in the solid electrolyte around the electrode/solid electrolyte interface. Oxide-based all-solid-state battery was introduced into the ERD chamber, and the battery charging reaction was carried out in it. The lithium concentration change in the electrode was observed by the ERD, which was consistent with electrochemical data (open circuit voltage curve). Based on these data, we next investigated the lithium concentration change around the solid electrolyte/current collector interface at a given applied voltage and detected a lithium concetration change region around the interface. Role of such lithium concentration change on the charge-discharge reaqctions will be discussed.