In a touch sensor, one ends of optical fibers are disposed at positions corresponding to respective pressure sensing points on a sensor sheet. The optical fibers in a bundled form are connected in a detection unit. The detection unit includes therein a camera that takes an image showing a change in luminance at the other ends of the optical fibers. A transmissive body is disposed to contain the other ends of the optical fibers and light sources. Upper and side faces of the transmissive body are covered with antireflection members. The transmissive body has substantially the same refractive index as the core of each optical fiber. A force applied to the sensor sheet is detected based on the change in luminance at the other ends of the optical fibers shown in the image taken by the camera.