A 17-year-old boy suffering from a head injury in a motorcycle accident was admitted to our hospital. Computer tomography (CT) revealed a small acute subdural hematoma and a 5cmx3cmx3.5cm mass which contained both hypodense and hyperdense components over the cerebellar vermis. Under the impression of cerebellar hemorrhage, the mass was removed via a craniotomy. The pathological diagnosis was an intracranial dermoid cyst. The hypodense portion shown in CT scan was revealed to be a keratinous waxy substance and that had hyperdensity was brown viscous fluid.