A loop locating apparatus and method enabling simple and fast identification of a Layer 3 loop fault occurring in a network, wherein, when the possibility of a Layer 3 loop is detected, a loop locating command function unit makes a packet transmission/reception function unit send a series of inspection packets (Pis) with successively incremented TTLs and monitors the return packets (te) of the inspection packets (Pis) by a return number counting function unit and wherein a loop location decision function unit finds the routers returning packets (te) with remarkably larger return numbers than the others and identifies the routers with return numbers over a predetermined threshold as the location of occurrence of the loop.