The transaction is subject to regulatory approval, which is being sought from the Office of Fair Trading.
The North Devon business, which has around 100 employees and a fleet of more than 30 buses, includes a small depot at Barnstaple.
It operates commercial and tendered bus services in Barnstaple, Ilfracombe, Braunton, Combe Martin, South Molton, Bideford and Great Torrington. The annual turnover of the business for the year ended 31 March 2011 was around £3million.
It is anticipated that the combined business will deliver a more sustainable combined bus network, allowing future investment in improved vehicles, more frequent services and good value fares.
The North Devon operations will become part of Stagecoach South West, headed by Managing Director Michelle Hargreaves.
Stagecoach South West employs around 900 people and operates more than 320 buses on around 120 routes across Devon and Somerset. In the past three years, Stagecoach South West has invested more than £13 million in new buses for the region.
Les Warneford, Managing Director, Stagecoach UK Bus, said: "Stagecoach has a long tradition of operating high quality
services for people in the south-west of England and attracting people out of their cars and on to greener, smarter bus travel.
"We believe our acquisition of the North Devon business would deliver a more sustainable combined bus network for the long term. It would protect and improve services for the local community, help support future investment in better vehicles and offer good value fares for customers."
Thanks to Phil G and Martin Arrand for alerting us to this announcement