Abstract: According to an embodiment, a cordless ultrasonic surgery instrument comprises an end effector directly contacting a tissue for incision or suture of the tissue, a handpiece including at least one or more piezoelectric elements to transfer vibration energy to the end effector, a hand instrument including a controller controlling an operation of the end effector and controlling to increase power from a power source device, a shaft assembly coupled with the end effector, rotated by receiving the vibration energy from the handpiece, converting part of vibration energy according to the vibration into electrical energy, and collecting the electrical energy, and a battery supplying power to the handpiece to allow the handpiece to transfer the vibration energy to the end effector, the battery charged with the electrical energy transmitted from the shaft assembly.