Anti-ganglioside antibodies have been reported in various peripheral neuropathies, including Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, Fisher syndrome, monoclonal gammopathy-associated neuropathy, and other idiopathic neuropathies. To our knowledge, there has been no report of anti-ganglioside-positive sarcoidosis. We report a 62-year-old man with acute weakness of the limbs and sensory disturbance of the right arm and trunk resembling GBS. Soluble interleukin-2 receptor and angiotensin-converting enzyme levels were elevated. Anti-ganglioside antibodies (immunoglobulin G anti-N-acetylgalactosaminyl-GD1a antibody [IgG anti-GalNAc-GD1a antibody]) were detected. Neurophysiological examination demonstrated axonal neuropathy. Bilateral hilar lymphadenopathy was demonstrated on a chest CT scan, and abnormal uptake of 67 Gallium was detected by scintigraphy. The ratio of CD4 to CD8 was elevated in bronchoalveolar lavage fluid. Noncaseating epithelioid cell granulomas were detected in a specimen obtained via transbronchial lung biopsy. Because intravenous immunoglobulin did not improve the symptoms, we commenced steroid pulse therapy followed by oral prednisolone therapy. After steroid therapy, he recovered fully. Because the findings in our patient fulfilled the criteria for neurosarcoidosis, we diagnosed his illness as probable neurosarcoidosis. To the best of our knowledge, this is the first patient with GBS-like-onset neurosarcoidosis positive for anti-IgG anti-GalNAc-GD1a antibody.