The project will be located alongside the Ayrshire Central Hospital site in Irvine and provide 206 beds for people who need a level of care and rehabilitation that can only be provided by a stay in hospital.
Balfour Beatty will finance, design and construct the project and operate the concession for 25 years.
Construction work will start next month, with the new facility expected to be operational in summer 2016.
The project is being funded using the Scottish Government’s non-profit distributing model and ranks as the fastest of the current tranche to achieve financial close.
Balfour Beatty Investments’ Scotland Director, Stephen Gordon said: “We are delighted to bring this project to financial close, enabling construction to get underway.
“Balfour Beatty has extensive experience in the PPP health sector and we look forward to working with NHS Ayrshire & Arran to provide a high-quality healthcare facility for the local community.”