An ultrasound endoscope includes: a distal end portion that is provided on a distal end of an insertion portion； a curvature portion that is connected to a proximal end side of the distal end portion. in the insertion portion； a plurality of coaxial wires that are inserted into the curvature portion； a convex ultrasound transducer provided in the distal end portion； and a relay substrate that is disposed in the distal end portion, is connected to the ultrasound transducer, and is connected to the coaxial wires. The relay substrate includes a first surface that is connected to the ultrasound transducer, a second surface that is connected to the coaxial wires, and a third surface that is continuous to the first surface through a first flexure portion and is continuous to the second surface through a second flexure portion.
