The disclosed technology is directed to a treatment system comprises a power supply apparatus and a treatment instrument configured to communicate electrically with the power supply apparatus so as to perform a treatment on a biological tissue. The treatment instrument includes an end effector that transmits a high-frequency current delivered by a first electrical energy to the biological tissue. An electric element is configured to operate the end effector by being actuated using second electric energy. The power supply apparatus includes a processor configured to receive a stop command to cutoff the supply of the first electric energy and the second electric energy in a state in which the first electric energy and the second electric energy are supplied and determine whether or not the end effector is in contact with the biological tissue based on a parameter related to the first electric energy after receiving the stop command.
