A tissue mimicking phantom for ultrasonic treatment and a calibration device of an ultrasonic treatment device using the phantom are aimed to be provided. In order to dissolve the above-mentioned problems, the tissue mimicking phantom in accordance with the present invention is characterized by including an indicator agent which is denatured by an increase in temperature and which simulates an ultrasonic treatment effect, and a denaturation sensitivity controlling agent which is a different component from that of the indicator agent, which serves as a nucleus of cavitation at the time of ultrasonic irradiation, and which supports the increase in temperature and the denaturation of the indicator agent. The configuration makes it possible to obtain an tissue mimicking phantom which resolves the shortage of sensitivity, and which has excellent stability.
