A treatment system comprises a power supply device and a treatment tool configured to communicate electrically with the power supply device so as to perform an operation on a treatment target. The treatment tool includes a sheath and an end effector configured to detachably attach to the sheath and being capable of bending with respect to the sheath. The end effector includes an electric element used to apply a treatment energy to the treatment target using an electric energy. The power supply device includes a processor. The processor sets to increase an output of the electric energy to be supplied to the electric element at in a second state. The sheath and the end effector are bent at a predetermined angle with respect to one another, compared with a first state where the sheath and the end effector are disposed straight in line with one another.
