An intraluminal forward-looking ultrasound probe of 3 mm in diameter has been developed. We used the probe as transmitters and receivers to make ultrasound forward-looking and three-dimensional images, but many artifacts are observed because of strong directivity of the probe. For decreasing the directivity of the probe, a convex-shaped 1-3composite PZT transducer which is 0.7 mm in diameter and 0.75 mm curvature radius was fabricated, and low directivity feature was confirmed. A probe which has eight separated 13composite convex-shaped transducers is fabricated. The probe is 3 mm in diameter and a working channel is 0.5 mm in diameter. Acoustic pressure is measured using a hydrophone which is located 10 mm in front of the probe. The emitting acoustic pressure of 43 Pascal is realized with the fabricated probe. When the probe is used as transmitters and receivers, image of an aluminum rod is constructed.