Abstract: An access classifying device includes a tree building unit, a similarity-degree calculating unit, and a classifying unit. The tree building unit generates multiple trees, in which a first server and multiple second servers are nodes and commands for automatically transferring the sequence of accesses from the above-described first server to the above-described second servers are edges. The similarity-degree calculating unit calculates the degree of similarity between the above-described trees in accordance with the degree of matching between partial trees included in each of the above-described trees generated. The classifying unit classifies the above-described access in accordance with the above-described degree of similarity calculated.