Phra Vihara Somdej(S.P.) is a distinctively designed building of four gables with the part of the southern and the western gables being of two storys while the part of the eastern and the western gables having only a single store. The distinct feature of this Vihara is focused on its door and window panels of beautiful gilded and lacquered decoration And the stucco adornment of its niches and gables with glass inlaid Surrounding the royal monogram "S.P." of Queen Sauwabha Phongsri, The consort of King Chulalongkorn who built this building in 1902, in accordance with the will of her husband to serve as the Buddhist library known at that time as "Ho Buddasasana Sangraha". Two important Buddha image Phra Fang and the Replica of Phra Buddha Narasih, enshrined in this Vihara.