The museum was created in 1946 when two former military museums were merged, the Artillery Museum (established in 1860) and the Intendant Museum (created in 1928), under the name Hærmuséet. At first the museum was open only to military personnel, but was opened to the public in 1978 by King Olav V under the name of the Armed Forces Museum. The museum is located inside the Castle Square, in one of the old military arsenals from the 1860s. The main purpose of the museum is to show the Norwegian military history from the Viking Age to the present, and the museum consists of six departments:
- The ancient times, military history from the Viking era to 1814.
1814-1905
- Military history from 1814 to 1905.
1905-1940
- Military history from 1905-1940.
- Military history from 1940 to 1945,focusing on the land battles of World War II.
Naval battles
- Military history from 1940 to 1945, focusing on naval battles of World War II.
- After the war, military history from 1945 to present.
Tanks in front of the museum are M24 Chaffee and M48 Patton.
