Provided is an apparatus for measuring convergence and ceiling subsidence using a fiber bragg grating sensor. The apparatus includes a plurality of unit-fiber bragg grating sensor modules having a predetermined length and sequentially connected to each other, where each of the sensor modules comprises: a fiber bragg grating stain sensor installed in a protective tube to sense a variation of a length; an installing member installed in parallel to one side of the protective tube; a fiber bragg grating angle displacement sensor mounted on the installing member to measure angle displacement; bases provided at both ends of each sensor module to connect adjacent sensor modules to each other; and a fixing member and a fixing unit to fix both ends of the protective tube and the installing member to the bases, respectively. Each of the sensor modules continuously measures two-dimensional or three-dimensional convergence and ceiling subsidence. Thus, the plurality of fiber bragg grating sensors are sequentially mounted on a measuring target to measure a moving distance and angle displacement due to section strain, so that convergence and ceiling subsidence may be precisely measured.