A vehicle electronic key system acquires a vehicle vibration, which is a vibration generated in a vehicle, at a time of a driver's door of the vehicle being closed after a driver is presumed to get in the vehicle, and a key vibration, which is a vibration generated in an electronic key, at the time of the driver's door being closed after the driver is presumed to get in the vehicle. The system determines whether or not the vehicle vibration and the key vibration at the time of the driver's door being closed match each other, and permits an operation of a predetermined operation target device mounted in the vehicle on the condition that the vehicle vibration and the key vibration match each other.