We report a rare case of giant skull myofibroma occupying left anterior cranial fossa. A 53-year-old woman presented with left exophthalmos for 2 years. Neurological examination showed left exophthalmos, disturbance of bilateral visual acuity, and bitemporal hemianopsia. A CT scan revealed an ossifing mass at left anterior cranial fossa. On magnetic resonance images, the tumor showed iso-intensity on T 1-weighted image, heterogeneous high intensity on T 2-weighted image, and was heterogeneously well-enhanced after administration of Gd-DTPA. The tumor was fed mainly by middle meningeal artery. The patient underwent surgery and the tumor was removed totally. Histological diagnosis of the tumor was myofibroma. The patient has been followed every other month by MRI without any adjuvant therapy. There has been no tumor recurrence for 19 months. There is no other myofibroma in her body, therefore the patient was diagnosed as solitary myofibroma of the skull. Our case is the first report of solitary myofibroma of the skull because we could not find any reports on solitary myofibroma of the skull in the past literature.