Although rare, primary sternal chondrosarcoma (PSC) is the most common primary malignant chest wall tumor. Here, we report a rare case of PSC treated with partial sternal resection and reconstruction. A 47-year-old man presented with subcutaneous anterior chest wall mass and chest pain. Chest computed tomography (CT) at the previous hospital revealed a 4.5 cm chest wall tumor involving the sternum at the fourth to fifth ribs and surrounding soft tissues. Percutaneous needle biopsy was performed, and grade 1 PSC was suspected. The patient was referred to our hospital for surgical treatment. A skin incision was made to include the subcutaneous needle biopsy site. Tumor margin >3.0 cm was guaranteed, and partial sternal resection was performed with resection from bilateral third costal cartilages to the xiphoid process. Since two-thirds of the sternum was removed and the defect was wide, the chest wall was reconstructed using two layers of 15×15 cm polypropylene mesh. The postoperative course was uneventful and the patient did not show flail chest. He was discharged on postoperative day 5 and had no tumor recurrence for 2 years.