Rhabdomyosarcoma is the most common soft tissue sarcoma that typically occurs in children and adolescents and is rare in adults. Furthermore, as cardiac tumor is rare, adult cardiac rhabdomyosarcoma is a very rare entity. Here, we report the case of a 68-year-old woman with cardiac rhabdomyosarcoma who was successfully treated with eribulin. She presented with sudden loss of consciousness, which was attributed to the cardiac tumor. The tumor was resected by emergency surgery and was diagnosed as embryonal rhabdomyosarcoma. Although surgical treatment alleviated her symptoms, the residual tumor increased in size after surgery and required multimodal treatment. First-line chemotherapy with the vincristine, actinomycin D, and cyclophosphamide regimen had to be discontinued owing to adverse events, and thus eribulin was used as a second-line treatment. Eribulin was better tolerated and helped maintain a stable disease status for >18 months. This reported case of cardiac rhabdomyosarcoma is the first case to be successfully treated with eribulin over a relatively long period. Eribulin therapy may thus be a viable treatment alternative for rhabdomyosarcoma.