A localization system includes: n+1 number of luminescent devices, where n is an integer greater than or equal to one; and a position measurement device moving in each direction of n number of axes, wherein the luminescent device includes a luminescent unit, the luminescent unit emitting a light for measurement having an intensity that varies at a predetermined time cycle, the luminescent unit also emitting a light for identification including an information representing a position of the luminescent device, the luminescent unit emitting the light for measurement and the light for identification in synchrony with a phase of those emitted by another luminescent device; and the position measurement device includes a light reception unit, a position obtaining unit, a phase computation unit, a standard luminescent device selection unit, a phase difference computation unit, and a position computation unit.