前立腺癌の経直腸的方法による超音波診断法について述べた. / Since about twenty years ago, ultrasonic methods have been used for the detection of submarines, fish finding and flaw detection of metal. Now ultrasonics have been applied to medical purpose. Recently, many reports on ultrasonic diagnosis have been published, but only a few reports (Schlegel, Takahashi, Gotoh etc.) have appeared in the field of urology. In this paper, the authors will present the results of ultrasonic diagnosis of prostatic cancer.