The old centre, surrounded by ancient oak trees, is on land designated as a site of special scientific interest.
A contract with the council has been signed by the Royal Society for the Protection of Birds to construct and run the new one.
It will be built at Forest Corner, closer to Edwinstowe village.
The current visitor centre was built in 1977 and is regarded as outdated.
The last project proposed for Sherwood Forest in 2012 - a £13m theme park which included included a medieval-style village fair, a wildlife dome, an open-air theatre, a torture chamber-themed attraction, and an adventure play area - was abandoned when investment fell through.
The scheme will "save the county council between £7m and £8m over the course of the 20-year contract", the authority said.
It will be developed by an RSPB-led consortium, which will include Thoresby Estate, Continuum Attractions and The Sherwood Forest Trust.
A council spokesman said it will "protect and preserve the unique and impressive natural habitats of Sherwood Forest Country Park".
Construction will start in December 2016 with the opening expected by winter 2017.
Developers of a £5.3m visitor complex in Sherwood Forest will demolish the current centre, Nottinghamshire County Council has confirmed.