Kyujang-gak was an institution established by the King Jungjo's order to enshrine and edit the royal writings and autographs, and to help the revival of learning with more active services in collection, control, and use of the important materials. Furthermore, it was aimed in its establishment to promote the settlement of an innovative and ideal Royal Regime. In this paper, the Outer Kyujang-gak(外奎章閣) of Kangwha Magistracy(江華府), which was one of the lower branches of the Kyujanggak(奎章閣), will be treated, especially about its details of establishment, location, functions, the characteristics and value of its collection. After the Japanese invasion of Korea in 1592, the Historical Deposit Library(史庫) was established at the Kangwha Magistracy to take custody of the royal writings and autographs. An Annex(別庫) was built near by the Historical Deposit Library to enlarge the space in the reign of the King Hyojong. These spaces, however, become insufficient as the amount of materials deposited expanded, and custody for them was also not successful. Therefore, at the April of the 6th year of the King Jungjo's rule, the Outer Kyujang-gak was built at the east of the Temporary Palace(行宮) within Kangwha Magistracy, where the royal materials were deposited. This Outer Kynjang-gak was also called 'Kangdo Oe-gak(江都外閣)', 'Kyujang Oe-gak(奎章外閣)' or 'Simdo Oe-gak(心都外閣)', and its major function was to take custody of the materials and to hand them down to the next generations forever. The Kandwha Magistrate(江華留守) was responsible for the management of the Outer Kyujang-gak. Regular events for the book keeping were enshrinement, inventory and airing. In the 6th year in the reign of the King Jungjo, 4,892 volumes consisting of 762 titles were moved here from the Bon-gmodang(奉謨堂), the Seoseo(西序) in Main Palace, the Annex(別庫), the Deposit Library(史庫) mentioned above, the Kaegsa(客舍) and Chaeg-go(冊庫) within Kangwha Magistracy. By the end of the Joseon Dynasty, through fourteen times of addition altogether, the number of collection enshrined here reached 6,400 volumes consisting of 1,212 titles. The significance of this Outer Kyujang-gak established at the Kangwha Magistracy is in the point that this was one of the most important deopsit libraries of the Joseon Dynasty.