Traditional building technique has been used as the main technology in the field of architectural heritage conservation in South Korea. It has remained this way with very little resistance until now. But the time has come to question the appropriateness of traditional technique as conservation technique. In this paper a study was done on the properties of the traditional technique and the architectural heritage conservation technique in order to define the appropriateness between the two techniques. As a result the traditional technique was found to be unfit for conservation technique. The reasons are as follows. First, there is a time gap between the traditional technique and the time when the heritage was first built. Second, conservation work is about retaining the values of being a heritage while the traditional technique is about safeness and practicality. Third, the use of traditional technique comes with using the tools of its time which cannot ensure the safety of the heritage. The traditional technique must be looked upon as one of an option in the field of conservation. We must develop a better conservation technology by finding balance between the traditional technique and modern science. And further more an aggressive investment must be made in order to realize this objective.

This study is conservation works trend since 1900. Objects for study are National Treasures and Treasures in Buddhism, in wooden architecture. And researched about the factor of conservation works, roof and tile, painting and dissolution conservation works cycle by dissolution, timber change ratio. The factor of conservation works is the most, roof and tile. Conservation works cycle by dissolution is 12.8 years. Painting cycle is 16.3 years. There are two concepts of conservation works, that is restoration and preservation. There are many restoration before 1960's. To 1960's the preservation to be many to 1970's many Restoration. And since the end of 1970's is Preservation. These reasons are conservation works history of object, the rule for Heritage protection, people on works, and study of architecture. history.

Most of researches in Korea by far on Sekino Tadashi were mainly focused on his historical view only. The main observations of this study, instead, are that; (1) his methodology of studying architectural history was closely related to his previous experiences with the conservation of the architectural heritages in Japan, and (2) his earlier activities in Korea made a significant Influence on the conservation of the architectural heritages in Korea. Sekino started his carrier after the graduation from the university by participating in the restoration sites of the architectural heritages in Japan, and his experiences at that time had founded the basis of his methodology of studying architectural history. Later, his on-site experiences were also adapted into the conservation of the architectural heritages in Korea when Korea was about to be colonized by Japan. In other words, Sekino's study on the Korean traditional architectures started from 1902 had a meaning of not only the starting point of the study on the Korean architectural history but also the starting point of the conservation of the Korean architectural heritages. Especially, Sekino's study during 1909 1912 prioritized the conservation of the architectural heritages as the main purpose of the study, and the influences of the study spanned over the entire colonial period by Japan. The influences were that; (1) Sekino's studies in 1909 1912 had outlined the colonial government's policy of the conservation of the architectural heritages, and (2) many restorations were made based on those studies.