1. A dividing device comprising: a memory configured to store a program; and a processor coupled to the memory, the processor configured to execute a process by the program, the process including: extracting correlation information from source code of software, the information correlating relationships between an originating entity of a relationship and a receiving entity of the relationship, which are identified by dependent relationships of a group of entities, which is the group of elements that structure the software, and dividing the group of entities into clusters, so as to be included in a cluster a lot of the dependent relationships for which a weight related to the dependent relationships is large, based on the weight related to the dependent relationships identified by the correlation information extracted by the extracting, wherein the dividing includes: dividing the group of entities into clusters, wherein a total weight related to the dependent relationships is larger than the expected value of the weight, based on the weight related to the dependent relationships identified by the correlation information extracted by the extracting.