The utility model provides a crack monitoring device, includes PC terminal, signal receiving and processing unit, laser rangefinder processing unit, cooperative target swivel -joint point. PC terminal connection signal receiving and processing unit, signal receiving and processing unit and laser rangefinder processing unit remote communication are connected. The cooperative target swivel -joint point is including rectangular prism, protecting sheathing, cavity spheroid. Laser rangefinder processing unit's one end fix the crack on one side, the cavity spheroid one end that cooperative target swivel -joint order is fixed at the crack another side, scalable hollow mechanism accompanys fissured development flexible, the PC terminal is used for accomplishing the data acquisition that develops in the crack, realizes fissured real -time supervision. The utility model relates to a crack monitoring device can real -time supervision fracture width development situation to through wireless dispensing device with data transmission to the receiving terminal of monitoring station, realize that indoor control predicts within range engineering structure or the fissured real -time width of the ground body, provide data for engineering structure or the genetic analysis of ground body disease, the evaluation of safety and health situation.