IN-VEHICLE MANAGEMENT DEVICE AND MANAGEMENT METHOD

The in-vehicle management device includes: a detection unit configured to detect the presence of a target device that is an in-vehicle device that does not support a predetermined message among in-vehicle devices included in an in-vehicle network; and a control unit configured to perform control for causing the target device detected by the detection unit to transition to a sleep state when a state where the predetermined message from the in-vehicle devices does not arrive at the in-vehicle management device has continued for a predetermined period.