PROBLEM TO BE SOLVED: To provide a pacifier type sensor that has a novel configuration.SOLUTION: A first sensor 42 and a second sensor 44 configured as reflective photoregistors, are wrapped by a cotton batting-like member 46, and are disposed in a tip part and the central part of the inside of a nipple-like part 58. When an external force does not act on the nipple part 58, a density of the cotton batting-like member 46 is adjusted so that detected voltages by the first sensor 42 and the second sensor 44 become the maximum voltages. When the nipple part 58 is deformed by the action of an external force, the density of the cotton-like member 46 is changed and amounts of lights received by the first sensor 42 and the second sensor 44 are changed, so that the detected signals of the first sensor 42 and the second sensor 44 are changed. Accordingly, a complex form of deformation of the nipple part 58 due to lip movement of a person wearing it can be identified more properly.
