The castle was originally built as a chapel, in 1379, thought to be dedicated to St Michael. Antiquarian William Worcester recorded that there were 32 castles on the Cornish peninsula, including Carn Brea which was described as a tower. The castle was extensively rebuilt in later periods, primarily in the 18th century by the Basset family as a hunting lodge. It is considered a folly, due to the huge uncut boulders that make up part of its foundations, giving the impression of the building melting into the land. It is now the location of a middle-eastern cuisine restaurant.