A wireless communication system includes: a locking and unlocking device configured to control locking and unlocking of a target, the locking and unlocking device including a device-side communication module configured to communicate a first signal having a first frequency band; and a key unit configured to command the locking and unlocking of the target by communicating with the locking and unlocking device. The key unit includes a unit-side communication module that communicates the first signal. The key unit is installed in the target such that a distance between the unit-side communication module and the device-side communication module is within a predetermined distance at which communication between the unit-side communication module and the device-side communication module is possible and that an axis of the unit-side antenna coil of the unit-side communication module is parallel to the axis of the device-side antenna coil.