In an ultrasonic probe of the present invention, a probe main body that comprises a flat shaped piezoelectric element group having a plurality of strip shaped piezoelectric elements arranged in a line in the major axis direction, which is the crosswise direction of the piezoelectric elements, is formed and housed within a container main body and sealed therein with a cover. The ultrasonic probe is characterized in that, in order to mechanically and linearly scan the probe main body in the minor axis direction, which is the lengthwise direction of the piezoelectric elements, the probe main body is linearly reciprocated and mechanically scanned in the minor axis direction, by an endless belt that is driven by a drive source via another endless belt linearly in the minor axis direction, while being guided by a pair of linear guides. As a result, sufficient movement stroke of the probe main body in the minor axis direction can be ensured, and by means of a movement mechanism comprising the endless belt, the probe main body can be reciprocated in the minor axis direction to the fullest extent between the inner walls of a sealed container.