Beckworth Emporium in Mears Ashby was robbed of cash from its safe this morning.
The robbery happened at about 4.45am, when about four men broke into the garden centre, restaurant and food hall and threatened a member of staff.
They stole cash from the safe and escaped in a 2012 black three-door Astra GTC.
Officers are appealing for witnesses and anyone with information is asked to call Wellingborough CID on 101.
They are particularly keen to speak to anyone who may have seen the black Astra or anyone acting suspiciously in the area around Mears Ashby and nearby roads and villages, around the time of the robbery.
Anyone with information is asked to call Northamptonshire Police on 101. Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.