The museum building is located near the school headquarters building. It is a two-storey building and one underground floor. It was built in 1987 on the occasion of the 100-year anniversary of this school in order to commemorate His Majesty King Chulalongkorn; or as the cadets call him "Sadej Pu" who founded the school. It is also used to organize the history of the school and honor the history of the alumni In the basement there is a multimedia briefing room for the school affairs, as well as displaying supplies and textbooks in various formulas such as the Army Course. There is also a history of 28 first and only female cadet cadets in the era of Field Marshal Plaek Phibun Songkhram, the dining table of Field Marshal Plaek Phibun Songkhram when he was poisoned by a cook, the costume he wore when he got assassinated and many more. 1st floor exhibits the honor of the R.E.R. alumni such as General Phraya Phaholpolyuhasena and Field Marshal Sarit Thanarat. There is also an exhibition of World War I operations, the Great War. Asia Brupa and the Korean War, including the school's Thongchai Chalermphon which is something that is very valuable and hard to find The 2nd floor exhibits a life-sized statue of King Rama V in the royal uniform of the Royal Thai Army Marshal, as well as a story about the origin of the Royal Thai Army, the first audio equipment show of His Majesty the King, Her Royal Highness Princess Maha Chakri Sirindhorn's desk as the teacher of the school.