Crowned dens syndrome (CDS) is a rare disease which presents with neck pain and rigidity. A 74-year-old man with right chronic subdural hematoma (CSDH) underwent hematoma drainage. After the operation, he complained of neck pain and laboratory test revealed elevation of C-reactive protein (CRP) and white blood cell (WBC). Suspecting localized infection, wound irrigation was performed. Neck pain relieved after irrigation, but we could not find the source of infection. CDS was diagnosed by computed tomography (CT). CDS is frequently misdiagnosed as meningitis and localized infection. CT is useful for diagnosis. Neurosurgeons need to be aware of CDS after operation.