Abstract: A bearing device includes: at least one bearing that has a rolling element and a raceway surface to support a main shaft; a member disposed on a path through which pressing force generating a preload between the rolling element and the raceway surface is transmitted; and at least one load sensor element fixed to the member to measure the pressing force. At least one load sensor element is a chip component including a thin film pattern of which resistance changes according to the pressing force and a protective layer that insulates and protects thin film pattern.

Abstract: A load sensor element includes a substrate made of a ceramic material; an inorganic layer having a surface configured to receive a load, the inorganic layer covers a portion of the substrate; a thin-layer resistance body whose resistance value changes in accordance with the load received by the inorganic layer, the thin-layer resistance body having a main body portion and a pair of end portions, the main body portion mounted on the covered portion of the substrate and sandwiched between the substrate and the inorganic layer, the pair of end portions mounted on an exposed portion of the substrate, and the exposed portion free of the inorganic layer; and a pair of electrodes electrically connected to the pair of end portions of the thin-layer resistance body and separated away from the inorganic layer and on one side of the substrate.