We report a case of idiopathic calcinosis of the scrotum. The patient was a 33-year-old male with a complaint of multiple scrotal nodules, from which white chalky materials occasionally broke out. The nodules were first noticed 17 years ago, and since then gradually increased in size and number. Sometimes he had felt itching on the scrotum, but otherwise he had been in good health. Blood analysis and biochemical analysis revealed normal findings. In addition, there were no abnormal findings in serum electrolyte analysis including calcium and phosphate concentrations. Analysis of the intra-nodular content by infrared spectrophotometry showed that it consisted of calcium phosphate (52%) and magnesium ammonium phosphate (48%). We reviewed the literature and discuss the etiology of this disease.