The great auricular nerve (GAN) is a sensory branch of the cervical plexus originating from the C2 and C3 nerve roots that innervates the external ear, mandibular angle, and parotid gland. Since idiopathic GAN neuralgia is a rare condition and branches of the GAN overlap with other cervical and cranial nerves, its diagnosis is challenging and can be confused with other facial neuralgias. This article describes the case of a 55-year-old woman with intractable unilateral periauricular and lateral head pain. No significant findings were found on cervical and brain imaging. At first, the patient was suspected to be suffering from trigeminal neuralgia or great occipital neuralgia; however, the symptoms persisted despite pharmacotherapy, cervical plexus and medial branch block, and repetitive transcranial magnetic stimulation. On the basis of an electrophysiologic examination, the patient was diagnosed as having GAN lesions. Pain subsided immediately after ultrasound-guided GAN block with local anesthetics and steroids. These findings indicate that electrophysiologic studies are helpful for accurately diagnosing patients with unclear pain in the periauricular and lateral head. Keywords: auricular pain, electrophysiologic study, facial pain, great auricular nerve, neuropathic pain