We report a 55-year-old woman with neuro-Behçet's disease with HLA B54 and predominant cerebral white matter lesions. She showed a cryptogenic high fever and cerebral cortical symptoms such as perseveration, limbkinetic apraxia and dementia. CSF study showed an increase of cell count and protein and a decrease of sugar. MRI showed diffuse T2-high signal intensity mainly in the subcortical white matter of left parieto-occipital lobes and basal ganglia. Her clinical signs greatly improved after administration of prednisolone. Her HLA type was not B51 but B54. Though our patient did not completely satisfy clinical criteria for neither neuro-Behçet's disease nor Sweet's syndrome, she showed partial features of both Behçet's disease and Sweet's syndrome.