This ultrasonic endoscope has: a hard section (11) that is provided on the leading end side of an inserting section; an ultrasonic probe (21), which is provided in the hard section (11), and which transmits/receives ultrasonic signals; a cable (27), which transmits electric signals to be inputted to and outputted from the ultrasonic probe (21); and a rigid flexible substrate (24), which is disposed between the ultrasonic probe (21) and the cable (27) so as to transmit the electric signals, and which is configured by having a part of a planar member as a flexible section (25) that includes an additional insulating layer, and another part of the planar member as a rigid section (26) that includes an additional hard layer, said planar member having a plurality of layers, including a wiring layer, laminated therein. The ultrasonic probe (21) is connected to the rigid section (26), and at least a part of the flexible section (25) is spirally disposed to surround a wiring connecting section between the cable (27) and the rigid flexible substrate (24).