Alveolar soft part sarcoma (ASPS) is a rare form of soft tissue sarcoma, and frequently, metastases are found at diagnosis. In patients with metastatic or unresected ASPS, systemic treatment is extremely limited, because conventional chemotherapeutic agents have not been effective in most cases. A novel agent inhibiting angiogenesis, pazopanib, has been proven to be effective for metastatic soft tissue sarcoma in a second-line setting. However, the efficacy of pazopanib in ASPS has not yet been reported. A 22-year-old man presented with right calf ASPS and multiple lung metastases. Pazopanib as a second-line treatment showed significant tumor response. To the best of our knowledge, this is the first report of the effectiveness of pazopanib in ASPS.