Large cell calcifying Sertoli cell tumor is a rare type of testicular  tumor.  Reported  herein  is  a  Japanese  patient with this tumor not associated with Carney's complex. An 11‐year‐old boy was admitted to hospital because of left testicular enlargement, and radical orchiectomy was performed. Macroscopically, the tumor was well circumscribed and had a maximum diameter of approximately 2 cm. The cut surface showed a yellow‐white solid mass. Histologically, the tumor was composed of large neoplastic cells with abundant eosinophilic cytoplasm with a tubular, trabecular, and solid arrangement and loose myxoid stroma with irregularly shaped calcification. Immunohistochemically, the tumor cells were positive for vimentin, S‐100 protein, calretinin, inhibin‐α, melan‐A, and CD10, and type IV collagen and laminin were observed in the extracellular matrix around the tumor cells. The distributions of melan‐A, CD10, and mitochondria were characteristically patchy; in contrast, they were diffusely distributed in the cytoplasm in a control case of Leydig cell tumor. The differences in immunostaining patterns for melan‐A, CD10, and mitochondria as well as positivity for S‐100 protein‐β might be useful diagnostic hallmarks of large cell calcifying Sertoli cell tumor for discrimination from Leydig cell tumor.