A fault location device detects a communication device connected to a broken communication line from among communication devices that carry out communications between each other through a two-wire communication line. The communication device, when detecting a communication error, stores communication error time and a communication error counter accumulated value indicating accumulated counts of the communication error, changes into a bus off state on the basis of the communication error counter accumulated value, and, after a predetermined period of time, returns from the bus off state. The fault location device includes an acquisition unit that acquires the communication error time and communication error counter accumulated value, stored in each communication device; and a detection unit that detects a communication device connected to a broken communication line on the basis of variations in the communication error counter accumulated values while any one of the communication devices is in a bus off state.