Devon and Somerset Fire and Rescue Service were called to the scene in Mark at around 5am on Sunday (January 29) to reports of a barn fire.
It was confirmed there was a fire within a beam at the front of the barn and firefighters extinguished the blaze using a hose reel jet and small tools.
At 5.35am, the fire crews requested the attendance of the rescue tender to help stabilise the building.
A Devon and Somerset Fire Service spokesman said: “Crews were cutting away using small tools and used a thermal image camera to check for any fire spread. The rescue tender was turned back en route to the incident as crews confirmed the structure was secure.
"The fire was confirmed out at 6.11am. Sadly five lambs died in the fire. Duty of care was left with the farmer.”
Farmer Victoria Dimond told Farmers Guardian: "One of our barns went up in flames and took the lives of five of our lambs - one of the lambs was special - it was my pet.
"We lamb 600 ewes and milk 60 cows and the barn which set alight backs onto the cow shed.
"A guy who was passing by saw the flames and tried to wake us - if it wasn’t for him the barn and cow shed would have completely gone up.
"We are all so shocked. We don’t really know what happened but it is our poor orphan lambs which have suffered."