Energy control device, treatment system, and actuating method of energy control device

An energy control device for use in combination with an ultrasonic treatment instrument, the ultrasonic treatment instrument including an ultrasonic transducer configured to generate ultrasonic vibration by being supplied with electric energy, and an end effector configured to perform a treatment by using the ultrasonic vibration generated by the ultrasonic transducer, the energy control device comprising:

• an energy output source configured to output the electric energy to the ultrasonic transducer;
• and
• a processor configured to:
• detect an electric characteristic value in relation to the electric energy which is output to the ultrasonic transducer;
• detect, based on a detection result of the electric characteristic value, a gradual decrease start time at which the electric characteristic value starts a gradual decrease after the electric characteristic value gradually increases;
• calculate a time rate of change of the electric characteristic value;
• and
• execute, based on a fact that the time rate of change of the electric characteristic value become greater than a predetermined threshold after the gradual decrease start time, at least one of causing the energy output source to stop or reduce the output of the electric energy to the ultrasonic transducer, and notifying that the time rate of change become greater than the predetermined threshold.