An ultrasonic probe for arthroscopic surgery includes: a bend extending portion which is provided on a distal side of a probe main body and which extends to bend to a side of a second intersecting direction of the probe main body, when a certain direction intersecting the longitudinal axis is a first intersecting direction and a direction opposite to the first intersecting direction is a second intersecting direction； and a treatment portion which is provided on the distal side of the bend extending portion and which is configured to treat a treatment target.
