POWER SUPPLY CONTROL DEVICE AND POWER SUPPLY CONTROL METHOD

A power supply control device includes: a connection device provided in an inter-system line that connects a first system and a second system; and a controller configured to control the connection device. The controller is configured to control the connection device to cut off the inter-system line in response to a power supply failure of the first system or the second system being detected, execute a confirmation process for confirming a failed system based on changes in voltages of the first system and the second system in a first period, and execute, in a case where the failed system cannot be confirmed in the confirmation process, an estimation process for estimating, as an abnormal system, a system with a greater possibility to be abnormal, based on changes in voltages of the first system and the second system in a second period longer than the first period.