Hemicrania continua (HC) is an indomethacin-responsive headache, characterized by unilateral and continuous headaches with cranial autonomic symptoms. Various pathologies, including sinus-related conditions, are associated with HC. Here, we report the case of a 62-year-old man with HC and rhinosinusitis. The patient complained of a unilateral continuous headache with ipsilateral cranial autonomic symptoms, conjunctival injection, and eyelid edema for 20 months. HC was identified as a potential diagnosis based on the symptom criteria, and a response to indomethacin confirmed the diagnosis. Trigeminal autonomic cephalalgia should be considered in patients with unilateral headaches and cranial autonomic symptoms.