A junction box includes a cable connecting box, a cover covering the cable connecting box and a cable electrically connecting with the cable connecting box. The cable connecting box including an insulative box and a wire connecting module, the insulative box comprising a plurality of walls extending upwardly and a receiving cavity surround by the walls, the walls including a front wall defining a plurality of mounting holes for the cable passing through. The cover includes a plurality of separating walls extending downwardly from a peripheral of the cover to engage with the walls of the insulative box and a pretending wall being parallel to the separating wall and located in front of the front wall. The adding pretending wall provides a longer distance for the junction box to ensure a safe creepage distance for the user to use the junction box.