The hold up took place at a fast food outlet on Doric Way in Larne around 1.10 am this morning.
Two masked men, one carrying a hammer and one with a suspected gun, entered through the back door and threatened staff before escaping with cash.
A 33-year-old man was arrested a short time later during a follow up operation.
He was subsequently released on police bail pending further enquiries.
Detectives in Larne have appealed for anyone with information to contact them on the 101 non emergency number;…