The purpose of this study was to research hats for pyeonbok that were worn by Joseon's diplomatic delegate to Japan, that is, Tongsinsa since the 18th century, with references to the collection of conversations in writing and exchanged poems and paintings, literature, including Sahaengrok, and other paintings all of which are related to Tongsinsa. The findings of the study can be summarized as follows. First, the members of Tongsinsa that were delegated to Japan in the late Joseon Period included three leading officials or samsa, chief official interpreter or dangsang yeokgwan, general official interpreters or yeokgwan, high literary officials or jesulgwan, clerks or seogi, medical specialists or yangeui, physicians or euiwon, official dictators or sajagwan and official painters or hwawon. All these members wore pyeonbokpo when being on board at sea or staying at lodgings. At the same time, they wore hats for pyeonbok. Second, hats that the diplomatic delegates usually wore when dressed in pyeonbok include waryonggwan, jeongjagwan, dongpagwan, gohugwan, bokgeon, yeonyeopgwan, yukja unyeopgwan, banggwan,