Cases of Sparganum mansoni, caused by the plerocercoid larva of the tapeworm S. mansoni, occur throughout the world, particularly in Asian, Middle Eastern, and European countries. However, cases of infection with this parasite are rarely seen in Japan. Here, we present a case of a 61-year-old woman with a solitary subcutaneous nodule in left inner aspect of the thigh, from which a long, slender, whitish worm was surgically removed. The parasite was histopathologically identified as S. mansoni. Serological testing confirmed cure of the infection after surgical removal of the parasite. The authors advocate immunoserological examination in case of S. mansoni.