The main hall of the Seonunsa Temple was built during the years of King Jinheung of Silla and rebuilt in 1472 (the 3rd year of the reign of King Sejong of Joseon). However, it was burnt down during the Japanese Invasion of Korea in 1592 and rebuilt again in 1613 (5th year of King Gwanghaegun). Measuring 5 kan (a unit of measurement referring to the distance between two columns) by 3 kan, it was built in the dapo (multiple column-heads) style in which gongpos (column-heads) support the weight of the roof. On the side there are two high pillars instead of gongpo. The span between pillars is wide and the front and rear widths of building are narrow to have a long stable shape along the side. The refined, magnificent and highly decorative dapo (multiple column-heads) as well as floral lattice detachable doors are typical of the architectural style of the mid Joseon Dynasty. The column-heads on the rear side of building are simple in design, and the shape of the rear eaves is different from that of the front eaves. The wall is made of wooden boards and the ceiling beams are criss-crossed. The walls are painted in red and blue.