A probe includes a probe distal end body, a vibration transmission body and a heat dissipation unit. The probe distal end body includes a first electrode. The vibration transmission body is arranged to a proximal end of the probe distal end body. The vibration transmission body transmits ultrasonic vibration generated by an ultrasonic transducer to the probe distal end body, and transmits current to the first electrode. An interior surface of the probe distal end body and an interior surface of the vibration transmission body define an interior space. The heat dissipation unit dissipates heat generated at the probe distal end body, wherein at least a portion of the heat dissipation unit is arranged in the interior space defined by the probe distal end body and the vibration transmission body. A treatment instrument includes the probe and an end effector including a second electrode.
