The 62-year-old former James Bond star was travelling with his 14-year-old son Paris on Sunday. The "Tomorrow Never Dies" actor was pulled by security agents after the weapon showed up during routine scanning of his shoulder bag, reported Ace Showbiz.
In some pictures, Brosnan could be seen taking his belt off as he prepared to go through screening at the airport.
The "Survivor" actor was heard saying, "I can't believe this is happening," after being asked to be screened in a private area.
Brosnan later went for lunch with his son at a concession in departures area. His representative hasn't responded to any requests for comment.
Brosnan will next be seen in upcoming action-thriller flick "No Escape" alongside Owen Wilson, Lake Bell, Sterling Jerins and Spencer Garrett. Directed by John Erick Dowdle, the movie is scheduled to be released in the US on August 26.