Abstract: A sensor device that makes it possible to simultaneously measure a plurality of portions in a pipe while suppressing optical loss even when the diameter of the pipe is relatively small. The sensor device includes an optical fiber in which a plurality of FBG sensors are formed and a detection unit that causes light to be incident on the optical fiber and detects reflected light from at least one of the plurality of FBG sensors. The portion of the optical fiber in which the plurality of FBG sensors are formed is wound around a pipe so as to form a winding angle which is a perpendicular or acute angle with an axis of the pipe in a side view of the pipe viewed from the portion of the optical fiber in which the FBG sensors are formed.