KEY MANAGEMENT DEVICE, VEHICLE RENTAL SYSTEM, KEY MANAGEMENT METHOD, AND NON-TRANSITORY COMPUTER-READABLE RECORDING MEDIUM

A key management device includes a server configured to issue an electronic key of a vehicle to a user device, configured to acquire position information of the vehicle, and configured to invalidate the electronic key issued to the user device when a determination is made from the position information of the vehicle that the vehicle is present at a predetermined position.