It is well known that bone metastases from lung cancer are quite common. However, it is rare that metastases to the orbital bone (such as sphenoid bone) from lung cancer cause cranial nerve symptoms. An 80-year-old man was diagnosed as squamous cell lung cancer (cT2N3M0 stage IIIB) and treated with radical chemoradiotherapy. After a year and a half, the patient presented with visual impairment and nasal hemianopsia of the right eye. The CT scan and MRI showed destruction of the greater wing of the right sphenoid bone and involvement of the optic canal and superior orbital fissure. The patient was diagnosed as orbital apex syndrome with visual loss, dysfunction of right ocular movement, and progression of cranial nerve disorders. Palliative radiation therapy induced the attenuation of right facial pain, but not the improvement of cranial nerve symptoms. When impairment of visual acuity and field are observed during the clinical course of lung cancer, it is important to consider the possibility of metastases as the cause and to initiate exanimations and adequate therapy.