To provide a touch sensor which is simple in structure, not influenced by a change in environment and accurately detects a position.

Optical fibers 2 are provided in areas A-D which are divided in four areas, that is upper and lower, and left and right, and one end of each optical fiber 2 is provided with a light-emitting device 3 and the other end of the optical fiber 2 is provided with a light-receiving device 4. The deformations of the optical fibers 2 by pressing are detected by the light-receiving devices 4 to obtain press position information. Each light-receiving device 4 grasps the degrees of the deformations of the optical fibers 2 as a variation in light quantity or a state variation of a light speckle.