An information collection apparatus which collects, from a plurality of devices each having a plurality of states including a power-supply state indicating ON or OFF of a power-supply, state information indicating a state of each device, the apparatus (a) stores, in a first memory, the power-supply state of each device, (b) receives state information transmitted from each device whose state is changed, (c) rewrites, when a power-supply state information indicating the power-supply state is received, the power-supply state stored in the first memory in accordance with the obtained power-supply state information, (d) collects periodically the state information from each device whose power-supply state stored in the first memory is ON by issuing, at regular intervals, a first request for the state information to the device, and (e) transmits the state information collected periodically to an external apparatus.