A 59-year-old woman suffered from sudden onset of severe neck and back pain. She experienced right-side hemiparesis. Although the right-side hemiparesis soon disappeared, left-side hemiparesis developed. MRI of the brain was unremarkable. MRI of the cervical spine demonstrated hematoma in the left posterior epidural space at the C2/3 level. The spinal cord was compressed not only by a degenerative disc of the ventral region, but also by hematomas of the dorsal region. The unusual hemiparesis alternating from right-side to left-side in this case may have been caused by various factors, including cervical canal stenosis, the spread of hematoma, disturbance of blood flow, and distribution of stress and strain.