Herpes zoster ophthalmicus, in which orbital symptoms and signs appear before the onset of a skin rash, is very rare. We experienced such a case and therefore report on it via magnetic resonance imaging. A 48-year-old man with pain and swelling of left eye and headache presented 2 days before onset of a zoster skin rash. On orbital MRI, edematous thickening of the left lateral rectus muscle with high signal intensity was revealed. After contrast injection, the lateral rectus muscle demonstrated heterogenous enhancement. Also, diffuse contrast enhancement was noted at left preseptal space, lacrimal gland and periorbital soft tissue. The man was treated with antiviral agents and prednisolone. Two weeks later, he recovered from the skin manifestations and most of the orbital manifestations except for the diplopia and restricted lateral movement.