To provide an image processor, an image forming apparatus, a program management method and a management program for hierarchizing the dependency of a plurality of programs, and for managing the operation of a program according to the hierarchization result.

This image processor 10 is configured to store a plurality of programs 31 having dependency and a dependence information data 32 showing the dependency of the programs 31, and provided with: a configuration management means 71 for generating hierarchical structure information obtained by hierarchizing the dependency of the plurality of programs 31 based on the dependence information data 32; a hierarchical structure information table 80 in which the hierarchical structure information is stored; and an operation management means 72 for performing at least any one of the start, end, installation and uninstallation of the programs 31 by using the hierarchical structure information table 80.