A control apparatus comprises: a job processing section for acquiring, on input of selection application information into a multi-functional apparatus, setting condition corresponding to the selection application information from the multi-functional apparatus, and carrying out predetermined data processing corresponding to the setting condition; a job result transmission section for outputting to the multi-functional apparatus a process result given by the job processing section; and a display switch-over determining section for controlling the multi-functional apparatus to enable the multi-functional apparatus to accept input of a user ID and selection application information from another user during the data processing by the job processing section. In this way, the present invention realizes a multi-functional apparatus control system capable of accepting a job from a user when another user is using the application program.