The 66-year-old man was stabbed in the head and neck on Tuesday afternoon around 3.30 pm at Wolsey’s tackle shop on the Upper Newtownards Road.
The victim was taken to hospital but his condition is not yet known.
It unclear if the pensioner worked in the shop or not.
A 50-year-old man was arrested at the scene under the Offences Against the Person Act and possession of a prohibited weapon in a public place.
He is currently in the custody suite at Musgrave Street PSNI station being questioned by detectives.