To provide a locking/unlocking controller for a vehicle and a locking/unlocking control system for the vehicle, which can enhance the convenience of the vehicle by enabling the smooth locking control of a door lock depending on the use mode of a user, without the performance of complicated operations.

Two different values, that is, a reference set value and a special set value are prestored in a vehicle-side microcomputer 17, in accordance with the use mode of the user, in terms of time from an inability to communicate mutually with a portable machine to the setting of the door lock. While normally controlling locking according to the reference set value, the microcomputer 17 performs the locking control based on the special set value, when an operating switch 20 is operated. The microcomputer 17 automatically returns to the locking control based on the reference set value, after performing the locking control, based on the special set value, a prescribed number of times.