Introduction: Among malignant pericardial tumors, which appear to be scarcely seen, primary pericardial angiosarcoma is considered as one of the rarest ones. Case Report: A 51-year-old female presented with dyspnea on exertion and edema of lower limbs. Echocardiography showed pericardial effusion. Aspiration and biopsy of pericardium were reported as chronic pericarditis as well. In her third admission, dyspnea and orthopnea were on the increase. In serial echocardiography, restrictive pattern was seen despite small pericardial effusion, which suggests constrictive pericarditis(CP). Cardiac catheterization also confirmed CP. A palliative total pericardiectomy was performed and angiosarcoma was diagnosed based on histopathological and immunohistochemical reports. Conclusion: While there was no tumor source in breast, lungs, gastrointestinal, genitourinary, and reticuloendothelial system, the tumor was recognized as primary pericardial angiosarcoma. However, she died a few days after the initiation of chemotherapy due to cardiopulmonary arrest.