Although prompt diagnosis and emergent surgical intervention are important in acute spinal subdural hematoma (SSDH), some cases with spontaneous remission of symptom and hematoma without surgery have been reported. We present a case of acute nontraumatic SSDH presenting with transient left hemiplegia for 4 hours. A magnetic resonance imaging study of cervical spine confirmed SSDH with C3-6 cervical cord compression at the left side. The patient had conservative management without recurrence. Although hemiplegia is an unusual clinical manifestation of SSDH, it should be differentiated from that of cerebrovascular origin promptly. Conservative management may be an alternative therapeutic option for selective cases with transient neurological deficits.