ABNORMALITY DETECTION DEVICE, ABNORMALITY DETECTION METHOD, AND ABNORMALITY DETECTION SYSTEM

This abnormality detection device (1) has: an opening degree acquisition unit (141) that acquires a plurality of pieces of opening degree data that indicate the opening degree of a valve provided in avehicle (T) as measured during a prescribed period; an integration unit (142) that, by integrating a plurality of differences between a plurality of opening degree measured values indicated by the pieces of opening degree data acquired by the opening degree acquisition unit (141) and a valve opening degree target value, calculates an integrated value for said differences; and a determination unit(143) that determines that there is an abnormality in the vehicle (T) in the event that the integrated value integrated by the integration unit (142) is greater than a prescribed value. 种异常检测装置(1)具有：开度获取部(141)，获取在规定的期间测量的、表示车辆(T)所具备的阀门的开度的多个开度数据；累积运算部(142)，通过对开度获取部(141)获取的多个开度数据表示的多个开度实测值和阀门的开度目标值的多个差量进行累积运算来计算出差量的累积运算值，以及判断部(143)，在累积运算部(142)累积运算的累积运算值比规定的值大的情况下，判断为车辆(T)存在异常。