The company, which employs 3,000 people across its 240 discount food stores, is completing the conversion of the former Priory Cinema in Spring Bank West, Hull.
With a shop area of more than 5,600 sq ft the store will be the biggest in a network which now stretches from Northampton in the south to Amble, Northumberland.
The company opened its first outlet in 1979 in Holderness Road, Hull, and is still owned by the same family, with Michael, David and Andrew Heuck buying the business when their father, Malcolm Heuck, retired in 2003.
The investment will create three full-time jobs and seven part-time positions. Of its 3,000-plus workforce, Heron Foods employs more than 700 in the Hull area across its stores and distribution centre.