"He greeted artists and residents who applauded the new arrival with emotion," the official Communist Party newspaper Granma said, describing Castro's outing Wednesday evening to the Kcho Estudio Romerillo.
The art gallery is next to the 87-year-old Castro's residence in Havana's Romerillo neighbourhood.
The public appearance coincided with the 55th anniversary of Castro's triumphal entry to Havana following the overthrow of dictator Fulgencio Batista.
The government website www.Cubadebate.Cu ran a photograph of Castro, taken from behind as he was seated talking to the gallery's owner Alexis Leyva, a member of the Cuban national assembly who is also a painter.
The Cuban leader, who relinquished the presidency to his brother Raul in 2006 due to illness, last appeared in public in April when he opened a Havana school.
But he meets with visiting foreign leaders and writes newspaper columns.