Provided are an ultrasound probe, an element circuit thereof, and an ultrasound diagnostic device, whereby high image quality is possible and reduced size and lower cost are made possible. Provided is an ultrasound probe, comprising: a 2-D array transducer wherein a plurality of transducers are arrayed two-dimensionally and a 2-D array IC in which are formed, upon an IC substrate, drive circuits which are disposed upon each of the transducers of the 2-D array transducer to drive each of the transducers at different timings with a prescribed delay quantity, and common current sources which supply drive current to the transducers of the 2-D array transducer. The number n of the common current sources which are formed upon the IC substrate is fewer than the number N of the drive circuits which are formed upon the IC substrate.
