Market Cross Jewellers on Linthorpe Road in Middlesbrough was targeted on Tuesday by men carrying what were thought to be axes.
No-one was injured, and police have not released any details of what was taken.
In November, watches, and diamonds worth hundreds of thousands of pounds were stolen during a raid at the store's branch in Yarm.
A 24-year-old man from Manchester was arrested on 8 January in connection with that robbery and later bailed pending further inquiries.
Temporary Det Ch Insp John Ward said: "There are clearly similarities between [yesterday's] robbery and the one that took place in Yarm in November and numerous lines of inquiry are being pursued in both cases.
"Officers would like to speak to anyone who may have seen, or have knowledge of, a silver Citroen C Crosser motor vehicle bearing the registration plates MK60 XCD.
"We believe this vehicle was involved in the [Middlesbrough] robbery and it was later discovered abandoned in the car park next to Leader timber merchants on Newport Road, Middlesbrough.
"We would also appeal to local hoteliers and to those who run local bed and breakfast venues to alert us should they have had any guests who may have raised their suspicions over recent days and who may have spoken with a North West accent."
An armed raid at a jewellers could be linked to one at another branch three months ago, police have said.