Device for preventing a wrong coupling of a connector

A device for preventing a wrong coupling of a connector, comprising;

• a pair of connector housings to be coupled face to face with each other,
• a slider mounted on one of the connector housings so as to be freely slid, which is unable to be moved to an actual engaging position and is stopped at a temporary engaging position when both connector housings are incompletely coupled as well as is able to be moved to the actual engaging position when they are completely coupled,
• a release projection, which is provided on the back wall of the other connector housing so as to project from it, for cancelling a temporary engagement of the slider by entering into an insertion space of one connector housing when the connector housings are completely coupled,
• a reinforcing rib provided at a specified position on the circumferential surface of the release projection, and
• a reinforcing rib accommodating part provided continuously with the insertion space, which can accommodate only the reinforcing rib provided in a specified position and cannot accommodate the reinforcing rib provided in any other position than the specified position.