Arrhythmia is treated with a simple treatment. Provided is an ultrasonic treatment apparatus including a long, thin probe to be inserted into a body, the probe having a contact surface that is brought into contact with tissue in the body and an ultrasonic generating device that radiates ultrasonic waves into the tissue through the contact surface； and a signal detecting portion that is provided at the contact surface of the probe and detects an electrical signal from the tissue. The ultrasonic generating device generates ultrasonic waves focused at a position on the other side of the contact surface from the ultrasonic generating device, the position being away from the contact surface in a direction intersecting the contact surface.
