It will close at 7pm on Wednesday and Thursday night.
Devon County Council will be carrying out urgent structural repairs on The River Exe Viaduct near Tiverton tonight (Wednesday 26th June) and tomorrow (Thursday 27th June).
They say an expansion joint at the eastern end of the viaduct near the Bolham roundabout is failing and needs to be replaced.
The A361 will be closed between Bolham and Ashmill from 7pm to 7am tonight and tomorrow night.
If the work is not completed in two evenings, an overnight closure is also provisionally booked for the evening of Friday 28 June.
During the closures, a signed diversion will be in place via the B3227 and A396.