Cornwall Council said it had been awarded more than Â£30,000 in grants to enable "essential works to be carried out" on the Grade II-listed Huer's Hut on the Towan headland.
The hut dates from the 19th Century, when Newquay was still a village and part of the pilchard industry.
The works were expected to take four weeks to complete, the council said.
The council - which has a long-term lease on the building, and is responsible for its repair and maintenance - said it had formally appointed contractor Ryearch to carry out the works on the hut.
Such huts provided shelter for lookouts, known as huers, who alerted fishermen to passing pilchard shoals.
Although the current building dated back to the mid-19th Century, the known history of the site went back to the 14th Century and it may have been a hermitage, the council said.
Work is due to start later in the autumn to repair a historic building in Newquay.