Leon Harrison, who runs the Shady Oak in Fernilee, also said he was frustrated with the county council because repair work has not even started yet despite the A5004 between Buxton and Whaley Bridge being closed more than a week ago.
He said: "It’s a very scary time for us.
“We have just managed to survive three lockdowns and lost two of our summer takings which would see us through the winter months.
"Now we have five months of road closures from Derbyshire County Council right over the summer again.
"The most frustrating thing is the road has been shut a week and work hasn’t even been started so why close the road so early?”
Derbyshire County Council closed the road on April 25 to fix a landslip which first appeared in 2016 and has continued to get worse over the years.
The work, which is predicted to be finished by the end of September this year, will see the road closed in both directions as contractors dig down to bedrock, around six metres below the existing road level and putting in a reinforced earth retaining wall.
Leon says he has approached the council to ask for some financial help during this difficult time but was told he is not entitled.
He said: "We are a destination venue and people come and travel to us or see us as they are passing but we have already seen such a drop in trade and it’s only the first week – it’s very worrying.
"Last week we only took a third of what we would normally take at this time of year and it’s scary to think how this will continue between now and September.
“I understand the work has to happen but does the council really need to close all of the road?”
Leon took over the pub three and a half years ago and says he will stay open throughout the closures.
"We are open everyday, we have the fires on and we are warm and welcoming but sadly we just aren’t getting the customers through the door.
"Some people have promised to stand by us and have walked up and others followed the diversion via Elnor Lane which is great but as a business we need more people to come and visit us during this tough time.”
A Derbyshire County Council spokesperson said: “We can assure people work is being carried out to prepare the site ahead of the significant excavation work that is scheduled, although no one was on site over the bank holiday.
“The first week of the works has been about preparing the site and getting necessary cabins, welfare facilities and traffic management in place.
“Secure fencing is also being put in place to stop public access and work is starting on excavation and exposing of BT cabling, with the removal of extensive Japanese knotweed on the highway verge due to start next week.
“Residents and businesses were aware of the work starting, and the extent of the closure and access issues were discussed and agreed with them.
“We apologise for any inconvenience caused while this work is on-going.”