To clearly notify the operator of an external apparatus of each utilization propriety of a plurality of functions when trouble occurs, or when the trouble has been solved.

Troubles occurring in a plurality of mechanisms for respectively realizing the plurality of functions owned by the image forming apparatus 1 such as an image reading mechanism 21 and a printing mechanism 22 are sensed by a trouble sensing section 11. The utilization propriety of the plurality of functions by the sensed troubles is respectively determined by a function utilization propriety determining section 12 for each function. Function utilization propriety information which indicates the determination result is formed by a function utilization propriety information forming section 13. The function utilization propriety information is transmitted to client apparatus 2, 3 and 4 by a function utilization propriety information transmitting section 14. The client apparatus 2, 3 and 4 recognize the utilization propriety of respective functions owned by the image forming apparatus 1 by the trouble which has occurred in the image forming apparatus 1 depending on the received function utilization propriety information.