A method to actively control the supercooling of water is a critical issue in cold-energy storage and transport systems that use ice slurries. We experimentally studied the use of ultrasonic vibration to control the phase change from supercooled water to ice, and simulated the phase change assuming that ultrasonic-induced cavitation influences ice nucleation. The experimental results indicate that ultrasonic vibration strongly promotes the phase change from supercooled water to ice and that a reliable method to actively control the phase change by ultrasonic vibration can be realized. The results of the simulation agreed well with the experimental results.