A system management layer changes a current program with a program (door lock failure diagnosis judgment program, security judgment program, door lock judgment program, keyless entry judgment program or the like) to be executed by an application layer, in accordance with an operation mode of on-vehicle equipment. Priorities of programs are previously stored for each operation mode, and a priority judgment program contributes to judge the priority of operation request based on the operation mode. Thus, plural programs of each hierarchal layer are categorized into groups per operation mode, although complicating in the single hierarchal layer. Therefore, it is possible to prevent the priority judgment processing from complicating for the operation request output by each computer program.