From ancient times, it was the roof that was most emphasized among the external appearances of a building when the intention was to display the beauty of the building and its differentiation from other buildings. Among other elements, the ornamental roof tile installed at the end of the ridge of a roof is an architectural component that has both a structural function and ornamental function. Ornamental roof tiles of such great symbolism were changed and developed from early times under the influence of China. An example of chwidu (鷲頭), a roof ornamental component used to decorate buildings of authority (such as the royal family), was recently excavated off the coast of Taean. It is the only case in which an intact chwidu, exquisitely carved with the face of a dragon having a gaping mouth, was excavated. Hence, it was first compared with the chiwen (鴟吻) from the Ming and Qing periods, which are still installed on buildings in China. As a result, it was found that the chwidu has something in common with both the chiwen from the Ming period and the chiwen from the Qing period. An attempt was then made to establish the specific production periods of chwidu among cases similar to that excavated in Taean, based on archaeological evidence. Cases of similar shapes and patterns to those of the Taean chwidu include the chwidu of the Hoeamsa Temple Site in Yangju, the chwidu of Sungnyemun Gate in Seoul, and the chwidu of jeongjagak (丁字閣, T-shaped shrine) at Gyeongneung of Seooreung in Goyang. As for their respective production periods, the chwidu of the Hoeamsa Temple Site was dated at the 1400s, the chwidu of Sungnyemun Gate to 1479 at the latest, and the chwidu of Gyeongneung jeongjagak to about 1469, respectively. Therefore, it was established that the Taean chwidu is a chwidu of the early Joseon period, produced in the 1400s. On the other hand, judging from the textual records on chwidu, the producer of chwidu during the early Joseon period was identified as japsangjang (雜像匠), affiliated with Waseo (瓦署). In principle, the use of chwidu was limited to buildings of the royal family, and accordingly chwidu was used for the major quarters of a palace, the jeongjagak of royal tombs, and the main entrance to the capital city. Against this principle, however, chwidu was sometimes put on a temple or a monument house according to the need of the royal family. Besides, the possibility was confirmed that chwidu was also used for government office buildings, which are not spaces directly connected to the royal family. It seems that a specific building in which chwidu was installed existed within a provincial government office, although this data is of the late Joseon period. It is presumed that this was because government offices in gun (郡) or hyeon (縣) acted as the haenggung (行宮, temporary palace) during the king’s visit outside the royal palace.