An ultrasound probe and ultrasonic diagnosis apparatus that can maintain surface temperature of an ultrasound probe within a safe range, without reduction in performance. The ultrasound probe includes a casing, a transducer, an electronic circuit, and a heat-transfer construction. Elements of the transducer are aligned at one end of the casing and send out ultrasound waves in accordance with their respective delay times. The electronic circuit, disposed in the casing, includes a delay circuit setting delay times and pulsers for generating pulses in accordance with the delay times, the pulses being sent to the transducer. While the electronic circuit is being energized, the heat-transfer construction disposes a member having a low heat conductivity at least either between the electronic circuit and the casing or between the electronic circuit and the transducer. Thereby, heat from the electronic circuit is conducted to the other end of the casing.