In an ultrasonic probe, an insulation layer portion is formed on an outer surface of a probe main body portion. A first electrode portion provided on an outer surface of the insulation layer portion so that at least part of the first electrode portion is exposed to an outside in a treatment section, and at least part of a second electrode portion is exposed to the outside in the treatment section. The second electrode portion is electrically insulated from the first electrode portion by the insulation layer portion. The probe main body portion vibrates integrally with the insulation layer portion, the first electrode portion and the second electrode portion.