Currently, ultrasound diagnostic devices are widely used and have become an essential tool in the medical front, particularly in the field of obstetrics and gynecology. These diagnostic devices have high frequencies and a large power of irradiated ultrasound waves for improving their performance and expanding the fields of their application, but lately research is being conducted worldwide to verify the safety of these devices. At the Japan Society of Ultrasonics in Medicine (JSUM), the Ultrasound Equipment and Safety Committee is testing and verifying the safety of these devices. In recent years, JSUM has been examining imaging equipment that use acoustic radiation force from the perspective of their impact on human health. With this background in mind, we developed a thermal imaging-based measurement system that uses infrared cameras to measure the two-dimensional temperature distributions of cross-sections of a phantom prepared following IEC 60601-2-37. We first obtained the relationship between the temperature distribution and irradiated ultrasound output power. We also conducted temperature rise tests on the propagation direction of ultrasound waves for cases with and without a mimicking bone (acrylic). Hence, we were able to visualize the effect of the temperature rise on the bone and neighboring areas caused by the reflection of ultrasonic waves. Next, we examined the validity of thermal imaging by comparing these measurements with those obtained through the conventional thermocouple method. We further examined their validity by conducting numerical simulations and comparing the simulation results with the thermal imaging measurement results. We consider that developing an easy-to-use simulation program will enable technicians to predict the temperature distribution in the body and help raise awareness of safety.