An interference identification device according to the present invention includes a feature calculation unit that calculates, using an electromagnetic wave received during a sample data analysis length, at least one type of feature of the electromagnetic wave, an interference identification unit that identifies a cluster to which the at least one type of feature belongs, among a plurality of clusters, each of the plurality of clusters having a region defined in a cluster space in which one type of feature corresponds to one dimension, and a sample data analysis length update unit that updates the sample data analysis length based on a distance, in the cluster space, between the at least one type of feature and the cluster.