The Falcon crane driver had to be lowered down in a stretcher by emergency services at the Northern Quarter site in Manchester.
The man was then quickly admitted to hospital, where he is in stable condition.
A spokesman for Greater Manchester Police said: “We were called at around 9.15am this morning (17 September) following reports that a man had fallen ill while inside a crane on Oldham Street, Manchester.
“Emergency services are attending and police are assisting with road closures.”
Four fire engines along with the Technical Response Unit was involved in the rescue operation. They used used specialist height equipment, including an open air platform and turntable ladder, to reach a 42 year old man who was then assessed by North West Ambulance Service .
A fire services spokesman said: “The man was lowered to the ground using specialist rope equipment before being conveyed to hospital by NWAS.”