RELAY DEVICE, SLEEP CONTROL METHOD, AND SLEEP CONTROL PROGRAM

A relay device to be used in an in-vehicle system that includes three or more in-vehicle devices, the relay device includes: a state transition unit configured to cause the relay device in a sleep state to transition to a wake-up state when receiving a first wake-up request from a first in-vehicle device of the three or more in-vehicle devices; and a sleep control unit configured to select a second in-vehicle device from among the in-vehicle devices other than the first in-vehicle device and transmit a second wake-up request to the second in-vehicle device to cause the second in-vehicle device to transition to the wake-up state.