An ultrasonic endoscope, comprising: a plurality of ultrasonic vibrators; a distal end part including an ultrasonic observation portion that houses the plurality of ultrasonic vibrators and further including an endoscopic observation portion at a proximal end side of the ultrasonic observation portion; an electrically conductive endoscopic structure connected to the distal end part; a thermally conductive member (60, 61) connected to the plurality of ultrasonic vibrators; and an electrically insulating thermally conductive member connected to the endoscopic structure, wherein the thermally conductive member and the electrically insulating thermally conductive member are connected to each other, wherein the endoscopic structure is made of metal, wherein the thermally conductive member is an electrically/thermally conductive member and has a first thermally conductive member and a second thermally conductive member that connects the first thermally conductive member and the electrically insulating thermally conductive member to each other, wherein the first thermally conductive member is directly connected to the plurality of ultrasonic vibrators, wherein the second thermally conductive member has its distal end side connected to the first thermally conductive member, is disposed to extend in the distal end part to a proximal end side of the of the endoscopic observation portion, and has its proximal end side connected to the electrically insulating thermally conductive member, wherein the electrically insulating thermally conductive member has its distal end side connected to the proximal end side of the second thermally conductive member and has its proximal end side disposed in contact with the endoscopic structure, and wherein heat generated from the plurality of ultrasonic vibrators is released from the endoscope structure via the first thermally conductive member, the second thermally conductive member, and the electrically insulating thermally conductive member. a plurality of ultrasonic vibrators; a distal end part including an ultrasonic observation portion that houses the plurality of ultrasonic vibrators and further including an endoscopic observation portion at a proximal end side of the ultrasonic observation portion; an electrically conductive endoscopic structure connected to the distal end part; a thermally conductive member (60, 61) connected to the plurality of ultrasonic vibrators; and an electrically insulating thermally conductive member connected to the endoscopic structure, wherein the thermally conductive member and the electrically insulating thermally conductive member are connected to each other, wherein the endoscopic structure is made of metal, wherein the thermally conductive member is an electrically/thermally conductive member and has a first thermally conductive member and a second thermally conductive member that connects the first thermally conductive member and the electrically insulating thermally conductive member to each other, wherein the first thermally conductive member is directly connected to the plurality of ultrasonic vibrators, wherein the second thermally conductive member has its distal end side connected to the first thermally conductive member, is disposed to extend in the distal end part to a proximal end side of the of the endoscopic observation portion, and has its proximal end side connected to the electrically insulating thermally conductive member, wherein the electrically insulating thermally conductive member has its distal end side connected to the proximal end side of the second thermally conductive member and has its proximal end side disposed in contact with the endoscopic structure, and wherein heat generated from the plurality of ultrasonic vibrators is released from the endoscope structure via the first thermally conductive member, the second thermally conductive member, and the electrically insulating thermally conductive member.