An abnormality detection device includes: a measurement value acquiring unit configured to acquire input accelerations of n vehicles traveling along a track; and an abnormality determination unit configured to determine abnormality in the track at a track position at which the input accelerations are equal to or more than a threshold value in a case where it has detected that the input accelerations for all of the n vehicles are equal to or more than a threshold value, and determine abnormality in any one or a plurality of vehicles out of n−1 or less vehicles in the n vehicles at which the input accelerations are equal to or more than the threshold value in a case where it has detected that the input accelerations for the any one or a plurality of vehicles out of the n−1 or less vehicles in the n vehicles are equal to or more than the threshold value.