We here report a rare case of synovial sarcoma of the chest wall. A 71-year-old Japanese woman noticed a left anterior chest wall mass after twice having had surgery for lung cancer. An aspiration biopsy diagnosed synovial sarcoma. She then underwent a surgical resection. Pathology examination revealed a biphasic-type synovial sarcoma. When the prepared RNA from the tumor was subjected to a polymerase chain reaction, SYT-SSX1 fusion gene transcripts were demonstrated. Patients with the SYT-SSX1 fusion gene have a worse clinical outcome than patients with SYT-SSX2-positive tumors. After a second surgery, performed in 1 year later, there was no evidence of recurrence for 30 months; however, careful observation may be required.