Descending necrotizing mediastinitis implies infection originating from the neck, most commonly an oropharyngeal or odontogenic focus, that spreads in the cervical fascial spaces and descends into the mediastinum. Early diagnosis is essential because descending necrotizing mediastinitis can rapidly progress to septic shock and organ failure. A comprehensive review of the current data of descending necrotizing mediastinitis in Japan was carried out using PubMed and ICHUSHI from the last 5 years. The symptoms, origins, comorbid conditions, treatment modalities, complications, and survival rates were analyzed. Tonsillar and pharyngeal origin was more identified compared to odontogenic origin. More than one-third of patients were diabetic and 28% of them were not identified as having any comorbidity. Streptococcus sp. and anaerobes were most isolated, reflecting the microflora of the oral cavity. Of the broad antibiotics, carbapenem was the most used as treatment, and clindamycin was the most co-given. Mediastinal drainage approach varied widely and the optimal approach is controversial. Twenty-one patients were treated with video-assisted thoracic surgical drainage and 15 cases by percutaneous catheter drainage, whereas transcervical approach was applied in 25 patients and thoracotomy was carried out in 21 patients. The overall mortality was 5.6%. Many authors advocated that the most effective management tool is a high degree of clinical suspicion followed by prompt and adequate drainage with intensive care including hemodynamic and nutritional support and repeat computer tomographic monitoring.