A temperature sensor comprising: a sensor element including a thermosensitive body and a pair of electric wires (15,17) that are electrically connected to the thermosensitive body; a protective tube accommodating the sensor element; and a filling body that lies between the protective tube and the sensor element inside the protective tube; wherein the pair of electric wires (15,17) comprises a pair of first electric wires that are connected to the thermosensitive body, and a pair of second electric wires that are connected to the pair of first electric wires, respectively, wherein the second electric wires include core wires, and insulation coverings that cover the core wires, wherein the pair of second electric wires are drawn to the outside of the protective tube, thus forming drawn-out portions of the pair of second electric wires, wherein, in the temperature sensor, a side on which the thermosensitive body is provided is defined as a front side, and a side on which the second electric wires are drawn out is defined as a rear side, and wherein the first electric wires each include a first region in the front side, arranged so as to include a narrow distance between the first electric wires, a second region, arranged so as to include a distance between the first electric wires expanding continuously, and a third region in the rear side, arranged to include a wide distance between the first electric wires, wherein the front side of the first region is connected to the thermosensitive body, and the rear side is connected to the front side of the second region, the rear side of the second region is connected to the front side of the third region, and the rear side of the third region is connected to a respective one of the second electric wires, characterized in that the insulation coverings of the pair of second electric wires are separated from each other on a front side of the second electric wires at which the core wires of the pair of second electric wires are connected to the pair of first electric wires, a distance between the insulation coverings of the pair of second electric wires becomes smaller with increasing distance from the front side of the second electric wires to a rear side thereof, the insulation coverings of the second electric wires come in contact with each other at a predetermined position in the drawn-out portions of the pair of second electric wires, and in the inside of the protective tube, the filling body lies between the insulation coverings of the pair of second electric wires that are separated from each other. a sensor element including a thermosensitive body and a pair of electric wires (15,17) that are electrically connected to the thermosensitive body; a protective tube accommodating the sensor element; and a filling body that lies between the protective tube and the sensor element inside the protective tube; wherein the pair of electric wires (15,17) comprises a pair of first electric wires that are connected to the thermosensitive body, and a pair of second electric wires that are connected to the pair of first electric wires, respectively, wherein the second electric wires include core wires, and insulation coverings that cover the core wires, wherein the pair of second electric wires are drawn to the outside of the protective tube, thus forming drawn-out portions of the pair of second electric wires, wherein, in the temperature sensor, a side on which the thermosensitive body is provided is defined as a front side, and a side on which the second electric wires are drawn out is defined as a rear side, and wherein the first electric wires each include a first region in the front side, arranged so as to include a narrow distance between the first electric wires, a second region, arranged so as to include a distance between the first electric wires expanding continuously, and a third region in the rear side, arranged to include a wide distance between the first electric wires, wherein the front side of the first region is connected to the thermosensitive body, and the rear side is connected to the front side of the second region, the rear side of the second region is connected to the front side of the third region, and the rear side of the third region is connected to a respective one of the second electric wires, characterized in that the insulation coverings of the pair of second electric wires are separated from each other on a front side of the second electric wires at which the core wires of the pair of second electric wires are connected to the pair of first electric wires, a distance between the insulation coverings of the pair of second electric wires becomes smaller with increasing distance from the front side of the second electric wires to a rear side thereof, the insulation coverings of the second electric wires come in contact with each other at a predetermined position in the drawn-out portions of the pair of second electric wires, and in the inside of the protective tube, the filling body lies between the insulation coverings of the pair of second electric wires that are separated from each other.