A storage medium storing a program that causes a computer to execute a process, the process includes obtaining a plurality of test data used for analysis of a classifier; obtaining a plurality of approximation models approximated to the classifier, each of separation boundaries of the plurality of approximation models being approximated to a different part of a separation boundary of the classifier; specifying, for each of the approximation models, a test data having a highest similarity from among the test data; specifying, for each specified test data, an approximation model having a second highest similarity with the specified test data from among the approximation models; selecting, from among the approximation models, an exclusion target model whose error with the specified approximation model is the smallest for each specified test data; and outputting the plurality of approximation models from which the exclusion target model is excluded for each specified test data.