An ultrasonic endoscope (12, 12a, 100, 100a) comprising, at a distal end part thereof: an ultrasonic oscillator array (50, 114) in which a plurality of ultrasonic oscillators (48, 112) are arranged; a backing material layer (54, 118) that is laminated on a back surface side of the ultrasonic oscillator array and supports the plurality of ultrasonic oscillators, a shielded cable including a plurality of coaxial cables, each coaxial cable including a signal line and a metallic shield member disposed outside the signal line; a wiring part including a plurality of connecting parts that electrically connect the plurality of signal lines to the plurality of ultrasonic oscillators, respectively; a ground part that is constituted by the plurality of shield members and has heat conductivity; a sheet-like first heat-conduction member disposed on a side surface of the ultrasonic oscillator array, the first heat-conduction member being metallic foil having electrical conductivity and heat conductivity, wherein the first heat-conduction member is disposed on a side surface of a laminated body including the ultrasonic oscillator array and the backing material layer, and extends to a lower side of the backing material layer that is a side opposite to the ultrasonic oscillator array side; and a second heat-conduction member attached and connected to the first heat-conduction member so as to form an integrated member in which the first heat-conduction member and the second heat-conduction member are integrated with each other whereby the second heat-conduction member is thermally and electrically connected to the first heat-conduction member, the second heat-conduction member being a ground bar;, wherein the ground part is thermally connected to the second heat-conduction member, wherein the first heat-conduction member is pasted on the plurality of ultrasonic oscillators; and wherein the second heat-conduction member is integrated with the first heat-conduction member at a lower end part of the first heat-conduction member that is the side opposite to the ultrasonic oscillator array side. an ultrasonic oscillator array (50, 114) in which a plurality of ultrasonic oscillators (48, 112) are arranged; a backing material layer (54, 118) that is laminated on a back surface side of the ultrasonic oscillator array and supports the plurality of ultrasonic oscillators, a shielded cable including a plurality of coaxial cables, each coaxial cable including a signal line and a metallic shield member disposed outside the signal line; a wiring part including a plurality of connecting parts that electrically connect the plurality of signal lines to the plurality of ultrasonic oscillators, respectively; a ground part that is constituted by the plurality of shield members and has heat conductivity; a sheet-like first heat-conduction member disposed on a side surface of the ultrasonic oscillator array, the first heat-conduction member being metallic foil having electrical conductivity and heat conductivity, wherein the first heat-conduction member is disposed on a side surface of a laminated body including the ultrasonic oscillator array and the backing material layer, and extends to a lower side of the backing material layer that is a side opposite to the ultrasonic oscillator array side; and a second heat-conduction member attached and connected to the first heat-conduction member so as to form an integrated member in which the first heat-conduction member and the second heat-conduction member are integrated with each other whereby the second heat-conduction member is thermally and electrically connected to the first heat-conduction member, the second heat-conduction member being a ground bar;, wherein the ground part is thermally connected to the second heat-conduction member, wherein the first heat-conduction member is pasted on the plurality of ultrasonic oscillators; and wherein the second heat-conduction member is integrated with the first heat-conduction member at a lower end part of the first heat-conduction member that is the side opposite to the ultrasonic oscillator array side.