A sensor element , comprising: a thermosensitive body ; a pair of conductive wires electrically connected to the thermosensitive body ; and a first covering layer made of a first electrical insulator, the first covering layer covering the thermosensitive body , wherein: the pair of conductive wires include first regions that are connected to the thermosensitive body and include a small mutual distance, second regions that are respectively connected to the first regions and include a mutual distance continuously expanded, and third regions that are respectively connected to the second regions and include a mutual distance larger than the mutual distance of the first regions , conductors are exposed in all of the first regions , the second regions , and the third regions , each conductive wire comprises an extraction wire and a lead wire , each extraction wire comprising one of the first regions , one of the second regions and one of the third regions , and each third region being connected with one respective lead wire , and the first covering layer covers the first region and the second region of each extraction wire , characterized in that each extraction wire is independently covered with the first covering layer in the second region such that the first covering layer has a shape that widens a mutual gap between the extraction wires in the second regions resulting in the creepage distance between the second regions being greater than the minimum distance between the third regions . a thermosensitive body ; a pair of conductive wires electrically connected to the thermosensitive body ; and a first covering layer made of a first electrical insulator, the first covering layer covering the thermosensitive body , wherein: the pair of conductive wires include first regions that are connected to the thermosensitive body and include a small mutual distance, second regions that are respectively connected to the first regions and include a mutual distance continuously expanded, and third regions that are respectively connected to the second regions and include a mutual distance larger than the mutual distance of the first regions , conductors are exposed in all of the first regions , the second regions , and the third regions , each conductive wire comprises an extraction wire and a lead wire , each extraction wire comprising one of the first regions , one of the second regions and one of the third regions , and each third region being connected with one respective lead wire , and the first covering layer covers the first region and the second region of each extraction wire , the pair of conductive wires include first regions that are connected to the thermosensitive body and include a small mutual distance, second regions that are respectively connected to the first regions and include a mutual distance continuously expanded, and third regions that are respectively connected to the second regions and include a mutual distance larger than the mutual distance of the first regions , conductors are exposed in all of the first regions , the second regions , and the third regions , each conductive wire comprises an extraction wire and a lead wire , each extraction wire comprising one of the first regions , one of the second regions and one of the third regions , and each third region being connected with one respective lead wire , and the first covering layer covers the first region and the second region of each extraction wire , characterized in that each extraction wire is independently covered with the first covering layer in the second region such that the first covering layer has a shape that widens a mutual gap between the extraction wires in the second regions resulting in the creepage distance between the second regions being greater than the minimum distance between the third regions . <EOS>