PROBLEM TO BE SOLVED: To provide an accident detection device that can detect an accident while restricting reduction in acceleration detection sensitivity.SOLUTION: Acceleration sensors 11a and 12a detect acceleration to acquire a time from when the acceleration becomes equal to or larger than a predetermined threshold until when it becomes less than the threshold. When a condition based on the time is met, an accident of a railway vehicle 1 is detected. Thus, the acceleration sensors 11a and 12a with a smaller measuring range can be used without the necessity of adopting an acceleration sensor with a wider measuring range within which an expected maximum value of acceleration is present. As a result, reduction in a detection sensitivity of acceleration with a low G generated during normal running can be restricted, enabling accident detection while restricting the detection sensitivity reduction.
