We report herein a case of hyperacute onset of spontaneous cervical spinal subdural hematoma treated with methylprednisolone pulse therapy that showed good results. A 57-year-old man was admitted for posterior neck pain and paraparesis which occurred an hour ago. MRI revealed a ventral subdural hematoma distributed from the level of C1 down to T3, compressing the spinal cord. Conservative management with methylprednisolone pulse therapy was administered considering the patient's poor general condition. Although emergent surgical decompression is necessary in most cases of spinal subdural hematoma, conservative management with steroid therapy could be effective.