Acute progressive weakness in bulbar, neck and limbs is included in several differential diagnoses, including the pharyngeal-cervical-brachial (PCB) variant of Guillain-Barré syndrome (GBS). Patients with the PCB variant of GBS are reported to have localized diagnostic cervical spinal nerve abnormalities that can be examined by nerve ultrasonography (NUS) and magnetic resonance neurography (MRN). We herein report the case of a 77-year-old man with the PCB variant of GBS. Although the nerve conduction study (NCS) findings were indirect indicators for an early diagnosis, the combination of NCS and NUS was a useful complementary measure that facilitated an early diagnosis. MRN did not show any apparent diagnostic abnormalities. After early treatment, the patient was discharged and returned home.