An electronic heating/cooling device, comprising: a Peltier device that can come in contact with skin covering a large blood vessel, the Peltier device being an element to which electric power is supplied to heat or cool a human body; a heating medium circulation path thermally coupled to an opposite surface of the Peltier device from a surface that can come in contact with the skin; a pump that is a part of the heating medium circulation path and is configured to circulate a heating medium; and a battery configured to supply electric power to the pump and the Peltier device, wherein the heating medium circulation path is composed of a flexible, thermally conductive material having a tubular shape, holds the circulating heating medium in a tubular internal space in an airtight manner, and has a first electrode and a second electrode, the first and second electrodes (32, 33) being made of a flexible, electrically conductive material and being configured to supply the electric power from the battery to the Peltier device and the pump, wherein the first and second electrodes (32, 33) are electrically insulated from each other, and wherein the heating medium circulation path has a first and a second flexible, electrically conductive material portion made of the flexible, electrically conductive material, and a first and a second flexible, non-electrically conductive material portion made of a flexible, non-electrically conductive material, the first electrode is the first flexible, electrically conductive material portion, the second electrode is the second flexible, electrically conductive material portior characterized in that the first flexible, non-electrically conductive portion is coupled between one end of the first flexible, electrically conductive material portion and one end of the second flexible, electrically conductive material portion, and the second flexible, non-electrically conductive material is coupled between the other end of the first flexible, electrically conductive material portion and the other end of the second flexible, electrically conductive material portion, wherein the Peltier device is in thermal contact with the first or the second flexible, non-electrically conductive portion and wherein the battery, the pump, and the Peltier device each are electrically coupled to the first and the second flexible, electrically conductive material portion. a Peltier device that can come in contact with skin covering a large blood vessel, the Peltier device being an element to which electric power is supplied to heat or cool a human body; a heating medium circulation path thermally coupled to an opposite surface of the Peltier device from a surface that can come in contact with the skin; a pump that is a part of the heating medium circulation path and is configured to circulate a heating medium; and a battery configured to supply electric power to the pump and the Peltier device, wherein the heating medium circulation path is composed of a flexible, thermally conductive material having a tubular shape, holds the circulating heating medium in a tubular internal space in an airtight manner, and has a first electrode and a second electrode, the first and second electrodes (32, 33) being made of a flexible, electrically conductive material and being configured to supply the electric power from the battery to the Peltier device and the pump, wherein the first and second electrodes (32, 33) are electrically insulated from each other, and the heating medium circulation path has a first and a second flexible, electrically conductive material portion made of the flexible, electrically conductive material, and a first and a second flexible, non-electrically conductive material portion made of a flexible, non-electrically conductive material, the first electrode is the first flexible, electrically conductive material portion, the second electrode is the second flexible, electrically conductive material portior characterized in that the first flexible, non-electrically conductive portion is coupled between one end of the first flexible, electrically conductive material portion and one end of the second flexible, electrically conductive material portion, and the second flexible, non-electrically conductive material is coupled between the other end of the first flexible, electrically conductive material portion and the other end of the second flexible, electrically conductive material portion, wherein the Peltier device is in thermal contact with the first or the second flexible, non-electrically conductive portion and wherein the battery, the pump, and the Peltier device each are electrically coupled to the first and the second flexible, electrically conductive material portion.