An ultrasonic endoscope (12, 13, 312) comprising: a laminated body (47, 347) that comprises an ultrasonic transducer array (50, 350) in which a plurality of ultrasonic transducers (48, 348) are arranged, and a backing material layer (54, 354) that is disposed on a back surface side of the plurality of ultrasonic transducers (48, 348); a wiring board (60, 61, 360) that comprises a plurality of electrode pads (62, 362) each of which is electrically connected to a corresponding one of the plurality of ultrasonic transducers (48, 348) of the ultrasonic transducer array (50, 350); a plurality of shield cables that comprise a plurality of signal wires each of which is electrically connected to a corresponding one of the plurality of ultrasonic transducers (48, 348), and shield members for the plurality of signal wires, wherein the shield members of the plurality of shield cables are made of a metal; a wiring portion (64, 264, 364) on the wiring board (60, 61, 360), the wiring portion (64, 264, 364) comprising a plurality of connection portions (66, 266, 366) at each which a corresponding one of the plurality of signal wires of the plurality of shield cables is electrically connected to a corresponding one of the plurality of electrode pads (62, 362) of the wiring board (60, 61, 360); a ground portion (58, 68, 268, 292, 358, 368) that is electrically connected to the shield members of the shield cables and that has heat conductivity, wherein the ground portion (58, 68, 268, 292, 358, 368) is (i) a collective ground portion (58, 358) disposed on the plurality of coaxial cables at a position on the proximal end side of an ultrasonic endoscope (12, 13, 312) relative to the wiring board, the collective ground portion being an electroconductive member to which the shield members of the plurality of shield cables are electrically connected, or (ii) a ground bar (68, 268, 368) that is provided in the wiring portion (64, 264, 364) and to which the shield members are electrically connected, or (iii) a ground pad that is provided in the wiring board (60, 61, 360; and that is electrically connected to a ground bar (68, 268, 368) provided in the wiring board (60, 61, 360); and a first heat conductive member (72, 77, 272, 372) that is disposed on a side surface of the laminated body (47, 347) that comprises the ultrasonic transducer array (50, 350) and the backing material layer (54, 354), that extends beyond the backing material layer to a side opposite to the ultrasonic transducer array (50, 350) with respect to the backing material layer (54, 354), and that is thermally connected to the collective ground portion (58, 358) or the ground bar (68, 268, 368) or the ground pad. a laminated body (47, 347) that comprises an ultrasonic transducer array (50, 350) in which a plurality of ultrasonic transducers (48, 348) are arranged, and a backing material layer (54, 354) that is disposed on a back surface side of the plurality of ultrasonic transducers (48, 348); a wiring board (60, 61, 360) that comprises a plurality of electrode pads (62, 362) each of which is electrically connected to a corresponding one of the plurality of ultrasonic transducers (48, 348) of the ultrasonic transducer array (50, 350); a plurality of shield cables that comprise a plurality of signal wires each of which is electrically connected to a corresponding one of the plurality of ultrasonic transducers (48, 348), and shield members for the plurality of signal wires, wherein the shield members of the plurality of shield cables are made of a metal; a wiring portion (64, 264, 364) on the wiring board (60, 61, 360), the wiring portion (64, 264, 364) comprising a plurality of connection portions (66, 266, 366) at each which a corresponding one of the plurality of signal wires of the plurality of shield cables is electrically connected to a corresponding one of the plurality of electrode pads (62, 362) of the wiring board (60, 61, 360); a ground portion (58, 68, 268, 292, 358, 368) that is electrically connected to the shield members of the shield cables and that has heat conductivity, wherein the ground portion (58, 68, 268, 292, 358, 368) is (i) a collective ground portion (58, 358) disposed on the plurality of coaxial cables at a position on the proximal end side of an ultrasonic endoscope (12, 13, 312) relative to the wiring board, the collective ground portion being an electroconductive member to which the shield members of the plurality of shield cables are electrically connected, or (ii) a ground bar (68, 268, 368) that is provided in the wiring portion (64, 264, 364) and to which the shield members are electrically connected, or (iii) a ground pad that is provided in the wiring board (60, 61, 360; and that is electrically connected to a ground bar (68, 268, 368) provided in the wiring board (60, 61, 360); and a first heat conductive member (72, 77, 272, 372) that is disposed on a side surface of the laminated body (47, 347) that comprises the ultrasonic transducer array (50, 350) and the backing material layer (54, 354), that extends beyond the backing material layer to a side opposite to the ultrasonic transducer array (50, 350) with respect to the backing material layer (54, 354), and that is thermally connected to the collective ground portion (58, 358) or the ground bar (68, 268, 368) or the ground pad.