A 25-year-old woman, diagnosed with Sjögren's syndrome at age 20, presented with painful edema of her left neck. Three days later, she additionally complained of bilateral auricular pain, and her nasal cartilage was tender to palpation. She was diagnosed as having phlegmon on the basis of her neck findings. Anti-human cartilage antibodies were demonstrated by indirect immunofluorescence, and the diagnosis of relapsing polychondritis was established. The patient was administered antibiotics and a non-steroidal anti-inflammatory drug, and her symptoms gradually improved. Relapsing polychondritis is one of the possible complications of autoimmune diseases, and infection might be a precipitating factor for this disease.