The idea to establish a castle museum in Fülek came in 1941. The Franciscan monk Kelemen König formed a 'Castle Committee' to collect funds for the collection and to excavate the castle in Fülek. The archaeologist Dr. János Kalmár began the excavation works in 1944 but the war stopped both the excavation works and the establishment of the museum.

The first museum in the Slovak part of Nógrád was the Comitatus Countrz Literacz Museum established in 1951. It was degraded Municipal Museum in 1960. The Losonc Comitatus Country Literacy Museum moved to town in 1967 which had been located at the Gács Castle since its establishment in 1955. The Municipal Museum was annexed to it in 1976. From 1967 to 1984 two permanent exhibitions existed: the exhibition of the Municipal Museum was located in the downstairs room of the Franciscan Monastery while the exhibition of the Nógrád Museum in the 'Vigadó' buildings.

In 1984 the Nógrádi Museum was moved to Losonc, then in 1988 the permanent exhibition in the castle was taken down. Now there weren't any museums in the town.

In 1993 a new chapter begin in the history of the Fülek Museum. The Ministry of Culture donated part of the Municipal Museum Collection to the town of Fülek. The new Municipal Museum was part of the Municipal Cultural Center, with exhibitions held in three buildings of the 'Vigadó'. However, just 15 years passed when the institute had to be reorganized.

The idea to form a castle museum came again in 2005. In 2006-2007 the Bebek Tower in town was renovated. In April 2007 the Fülek Castle Museum was established located at the Fülek Castle. In August 2008 the Castle Museum opened the exhibition ’Centuries in the History of the Fülek Castle' held in the Bebek Tower. The material consisted of the scale model of the castle, finds from the Slovak National Museum, original keys to the castle and objects from the time of the Ottoman rule. The most important Archaeological finds were displayed downstairs. A few items of the 3000-year-old bronze finds and ceramics discovered at the excavation of the Bronze Age cemetery were borrowed from the Nógrád Museum and Gallery. Belts from the time of the Settlement of the Magyar are of extreme importance. The Municipal Country Literacy Museum is now affiliate of the Fülek Museum. The permanent exhibition was closed in the summer of 2008 as the building needs to be renovated. The new permanent exhibition presents the history of the town of Fülek after 1682.