Abstract: A junction box whose total size is reduced without reducing the areas necessary for accommodating fuse receptacles and relay receptacles. The body of the junction box is preferably a flat rectangular parallelepiped. On the first face thereof, there are integral relay receptacles, preferably adjacent one side in a single vertical row. On the opposite face, there is a plurality of fuse receptacles located adjacent the opposite side of the junction box and thereby spaced apart laterally from the relay receptacles. Those fuses which are relatively near to the relay receptacles are for apparatus which is not operated continuously, such as a rear windshield wiper, cigarette lighter, etc. On the four sides of the body are provided the locking members with which the junction box is fixed to the base, usually the chassis of an automotive vehicle.