Non-clostridial gas gangrene is a necrotizing soft tissue infection caused by a bacterium other than Clostridium spp. We report a case of non-clostridial cervical gas gangrene derived from dental infection in a patient with no serious underlying disease that required three anti-inflammatory surgeries. The patient, a 55-year-old man with a history of hypertension, presented to our emergency department in October 2017 because of worsening swelling in the submandibular region. General examination revealed that his temperature was 38.8 °C, blood pressure was 135/87 mmHg, and heart rate was 135 beats/min. The Sequential Organ Failure Assessment score was 1. The extraoral examination revealed marked swelling with erythema from the submental area to the left side of the cheek, and the opening was 20 mm. Intraoral examination revealed drainage of pus from the mouth and marked swelling of the floor of the mouth. CT scan showed gas in the right submandibular area, and the airway was highly stenotic. The patient was diagnosed with apical periodontitis of the right lower first molar and cervical gas gangrene, and tracheostomy and debridement of the cervical area were performed under general anesthesia on the same day. Doripenem 3 g and clindamycin 2.4 g were continued as antibacterial agents. Prevotella sp and Streptococcus constellatus were detected in the pus collected intraoperatively. After that, inflammation was finally controlled by additional debridement under general anesthesia on the 6th and 10th day of hospitalization, and the patient was discharged on the 44th day.