The ultrasonic probe has an element part which transmits and receives ultrasonic waves, a relay cable connected to the element part, which transmits a signal to the element part, a frame and a window constituting a housing part in which the element part and the relay cable are housed, and an oscillation mechanism which oscillates the element part. The oscillation mechanism has a rotation axis configured to provide oscillation movement of the element part. The relay cable has an S-shape or a reversed S-shape with two arc-shaped parts. One end of the relay cable is connected to a cable connecting surface of the element part and, when the element part is positioned at a middle of a scanning range, in a connected portion with the element part, the relay cable is drawn from a point connected to the element part in a direction substantially parallel to the cable connecting surface. The frame is placed on an opposite side of the rotation axis from the element part. The relay cable is electrically connected to an outer portion of the housing part.