It was also called Namdaemun because it was located in the south of the main gate of Hanyangdoseong during the Joseon Dynasty. It was built in 1396 (the 7th year of King Taejo's reign) and was the oldest wooden building in Seoul.

The building was rebuilt in 1448 (the 30th year of King Sejong's reign), and it was discovered that there was a big construction in the 10th year of King Seongjong's reign (1479) during the dismantling and repair of the building between 1961 and 1963.

Later, on February 10, 2008, the fire at Sungnyemun destroyed the roof of the second floor of the pavilion and partially destroyed the roof of the first floor. After five years and two months of restoration work, it was completed on May 4, 2013 and opened to the public.

This gate is a two-story building with a two-story square measuring 5 bays in front space and 2 bays in side space, with a rainbow-shaped gate in the middle of the stone pillars. The roof has a trapezoidal shape when viewed from the front, which is called the Woojingak roof. The multi-layered structure, which is decorated on the upper part of the pillars to support the eaves of the roof, is not only on top of the pillars but also between the pillars, and the composition is not too severe and is well-organized, showing the characteristics of the early Joseon Dynasty.

It is said that Yangnyeongdaegun wrote the Hyeonpan, which reads "Sungnyemun," in the book "Jibong Yuseol." It is the oldest wooden structure in Seoul that shows the exact date of construction.

ᄋ Sungnyemun's fire-fighting fire(2008.2.10)

- The 2008 Sungnyemun arson attack was a case in which the Sungnyemun building was burnt down from February 10 to February 11, 2008. The fire broke out around 8:40 p.m. on February 10, 2008, and the second floor of Sungnyemun collapsed around 0:40 a.m. on February 11, 2008, followed by a fire on the first floor, damaging buildings except stone pillars at 1:55 a.m., five hours after the fire.