An apparatus and method for detecting composite material damage due to impact by using distributed optical fiber are disclosed. In the apparatus and method for detecting composite material damage due to impact by using distributed optical fiber, the position and level of damage occurring in a composite material due to low-velocity impact can be effectively and economically detected by measuring the residual strain of optical fiber distributed on the surface of the composite material or inside the composite material. In the apparatus and method for detecting composite material damage due to impact by using distributed optical fiber, there is no need to always operate a sensor in real time, so that detection errors due to temporary failures, malfunctions, etc. of the sensor, as well as a problem of constantly supplying power to the sensor, can be essentially removed.