This building is the mullu (attic over the outer gate) of Yongjusa Temple, located on the skirt of Seonghwangsan Mountain of Hwaseong-si. A mullu literally refers to the building below the nugak (building that is two stories or higher) with a door for entering or exiting, and sometimes, a simple road is placed for people to pass by without a door on the bottom floor.
Cheonboru Gate is situated on flat land and formed in one tier of stylobate without a chukdae (building ground up higher). The first story is formed by combining the trapezoid-shaped high stone pillar and short wooden pillar, and the floor of the second story is made by building the flooring over the pillar once more. The second story has round wooden pillars, gongpo (wooden brackets assembled onto the capital to support the weight at the edge of the eaves) to support the roof and a gambrel roof that looks like the Chinese character for eight when seen from the side. To the sides of Cheonboru Gate, a corridor that connects to the yosa, the living quarters for the monks, is installed. Cheonboru Gate, the corridor and yosa are connected like a single building, making them appear like the gate and haenggak (building that lines up corridors and rooms in a straight line) of the royal palace.
One of the buildings that directly exhibits the character of Yongjusa Temple as a neungchimsachal (temple that protects the royal tomb) of Hyunreungwon, Cheonboru Gate is less elaborately decorated than the Buddhist hall where the Buddha is enshrined, but is quite large and splendid for a mullu (attic over the outer gate) of a general temple, and has a structure similar to the royal palace through connecting to the corridor and yosa on either sides.