Police say that at around 9.15 pm, four masked men forced their way into the house of a man, who is aged in his 80s.
It is believed that they were armed but it is unknown what type of weapon they had in their possession.
A sum of money was taken before the men made off from the scene in some sort of vehicle, heading in the direction of Kilcairn Road.
The man was not injured.
Detective Sergeant Reid said: “I would ask anyone with any information about this incident to contact detectives at Bangor Police Station on the non emergency number 101.
“Or if someone would prefer to provide information without giving their details, they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.”