A sensor according to the present disclosure includes a tubular needle member that defines a hollow portion, and a linear detection member that is located in the hollow portion, and a side wall of the needle member projects toward the hollow portion. A thick part is provided.本開示に係るセンサは、中空部を区画する管状の針部材と、前記中空部に位置する線状の検出部材と、を備え、前記針部材の側壁には、前記中空部に向かって張り出す厚肉部が設けられている。