A case of primary cardiac tumor is presented. Sonographic examination at 27 weeks' female gestation revealed a large tumor in the left ventricle of the fetal heart. After post-termination, the newborn died of congestive heart failure immediately. Autopsy demonstrated a large tumor in the left ventricle obliterating most of the left ventricular cavity. Microscopically, the cardiac tumor showed ”spider-cells” characteristics of rhabodomyoma.