A joint surgical system includes, a treatment tool, a high-frequency output section which outputs high-frequency energy to the treatment tool, an ultrasonic output section which outputs ultrasonic energy to the treatment tool, a measurement section which measures a temperature of the liquid, and a control section which controls the high-frequency output section to stop output of the high-frequency energy and controls the ultrasonic output section to continue output of the ultrasonic energy when a measurement temperature measured by the measurement section is equal to or higher than a predetermined temperature.