The phantom (10) comprises a large pectoral muscle simulating layer (21) which simulates the large pectoral muscle of the human body from the aspect of the ultrasonic wave propagation characteristic, and the mammary posterior posterior fat simulating layer (22) which is laminated in the large pectoral muscle simulation layer and simulated the fat layer of the posterior part of the human body from the aspect of the ultrasonic wave propagation characteristic.The phantom is also placed between the skin simulating layer (23) that simulates the skin layer on the surface of the breast from the aspect of the ultrasonic wave propagation characteristic, the subcutaneous fat simulating layer (24) which is attached to the interior of the skin simulated layer, simulates the subcutaneous fat of the breast, and the hypothalamic fat simulated layer and the subcutaneous fat simulating layer, and the breast gland It comprises at least a plurality of glandular leaf simulators (25) simulated from the aspect of ultrasonic propagation characteristics.At least one lesion simulating part (T1 (T2 to T4)) was simulated from the surface of the ultrasonic wave propagation characteristic to the multiple glandular cortex model (25). ファントム（１０）は、人体の大胸筋を超音波伝搬特性の面から模擬した大胸筋模擬層（２１）と、大胸筋模擬層に積層され、人体の後隙の脂肪層を超音波伝搬特性の面から模擬した乳腺後隙脂肪模擬層（２２）とを備える。ファントムは更に、乳房の表面の皮膚層を超音波伝搬特性の面から模擬した皮膚模擬層（２３）と、皮膚模擬層の内側に張り付けられ、乳房の皮下脂肪を模擬した皮下脂肪模擬層（２４）と、乳腺後隙脂肪模擬層と皮下脂肪模擬層との間に配置され、乳房の腺葉体を少なくとも前記超音波伝搬特性の面から模擬した複数の腺葉模擬体（２５）と、を備える。複数の腺葉模擬体（２５）に、乳房の病変を超音波伝搬特性の面から模擬した少なくとも１つの病変模擬部（Ｔ１（Ｔ２～Ｔ４）を設けた。
