An ultrasound endoscope 1 has an ultrasound probe 12 which is disposed at a distal end side of a distal end rigid portion 2a configuring a distal end portion out of a flexible tube portion 2c, a bending portion 2b and the distal end rigid portion 2a configuring an insertion portion 2, and forms an ultrasound scanning surface having a normal line in a direction orthogonal to an endoscope insertion axis L1, and a treatment instrument outlet 24 of a treatment hole 27 in the distal end rigid portion 2a. The ultrasound probe 12 is configured by a plurality of ultrasound transducers 9 arranged in a convex circular arc shape, and a center of curvature of the plurality of ultrasound transducers 9 is disposed at a proximal end side from the treatment instrument outlet 24.
