| 31 Building | |
| Native Name: | 삼일빌딩 |
| Native Name Lang: | ko |
| Coordinates: | 37.5686°N 126.9872°W |
| Address: | 85, Cheonggyecheon-ro, Jongno-gu, Seoul, South Korea |
| Building Type: | Office |
| Architectural Style: | International Style |
| Roof: | 110m (360feet) |
| Floor Count: | 31 (equivalent) |
| Architect: | Kim Chung-up |
| References: | [1] |
31 Building (also known as Samil Building,) is an office building in Seoul, South Korea. Completed in 1970, the 31 Building was the tallest building in Seoul until 1979, when Lotte Hotel Seoul was completed.
The architect of the 31 Building was Kim Chung-up, a famous architect in South Korea.
It was selected as 'Seoul Future Heritage' because it is considered a valuable building in the history of architecture in Seoul.