We report a case of a 3-year-old boy with acute muscle weakness that initially affected neck and all four limbs but later vanished from the lower limbs. Pharyngeal palsy was not observed during the course. All deep tendon reflexes were absent. Peripheral nerve conduction studies showed a demyelination pattern in each limb. The patient received intravenous high-dose corticosteroid hormone, followed by two immunoglobulin therapies. His muscle strength gradually improved after treatment and was almost completely restored four months later. We ultimately diagnosed the condition as the pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, in consideration of the patient's muscle weakness of the neck and four limbs, the greater degree of weakness of the upper limbs versus the lower limbs. His clinical presentation was atypical for the pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, as he presented no pharyngeal muscle weakness or anti GT1a antibodies, typical manifestations of the condition.