Small cell lung cancer (SCLC) is a neuroendocrine tumor, and the median age of onset is about 70 years old. A 20-year-old non-smoking man with known systemic sclerosis presented with discomfort in his left chest. Chest X-ray showed a mass shadow in the left upper zone. A transbronchial lung biopsy revealed small cell carcinoma, and imaging studies reached the diagnosis of extensive disease small cell lung cancer. He had concurrent interstitial lung disease with a non-specific interstitial pneumonia pattern and anti-Scl-70 antibodies. He died eight months after the diagnosis during fifth-line chemotherapy. We herein report the youngest case to date of SCLC with systemic sclerosis.