Scott & Charters has been operating from its Fairhurst Drive site in Hawick for more than 50 years.
It now wants to knock down its old building and put up a new two-storey structure in its place.
A statement said it would allow the company to continue manufacturing luxury knitwear in the town.
The works would be carried out in two phases, the first would see part of the existing building demolished but the rest of it retained during construction of the new facility.
Once that was completed the remainder of the old factory would be taken down.
A new access off Fairhurst Drive would also be formed and a new car park with 27 spaces created.
Plans have been lodged to demolish and replace a Borders knitwear factory to allow for "future growth and expansion".