A thin input device can be made small and thin, and prevent an excessive force from acting on a connecting part with a substrate when an operating part is operated to detect deformation of an actuating member. An actuating member is received in a recess of a lower case, and a lid is fixed. The actuating member includes fixed parts provided at four corners and deformable parts thinner than the fixed parts. The fixed parts are fixedly sandwiched between a bottom surface of the recess of the lower case and the lid. The deformable parts, to which strain detecting elements are attached, are provided in four directions around the operating part. When the operating knob is operated to deform a deformable part, the force acts only on the case, and an excessive force does not act on connecting parts between the connecting terminals, and a substrate.