To provide an information processing system which can perform power consumption control more effectively, by shifting devices with low use frequency to a sleep mode promptly.

When a certain image formation device shifts to the sleep mode, this device transmits a sleep notification packet including information of use frequency. When other image formation device receives the sleep notification packet, the device compares the frequency with its own use frequency in the use frequency information. When the device detects that a device whose use frequency is higher than its own use frequency, the device also shifts to the sleep mode.