A joint connector includes housings which can be stacked together, with a predetermined gap formed therebetween, each of the housings having a plurality of juxtaposed terminals received therein, and a circuit forming element which is inserted into the gap between the stacked housings, and connects arbitrarily-selected ones of the terminals in the adjacent housings, adjoining to each other in a stacking direction, and also connects arbitrarily-selected ones of the terminals in the same housing. By inserting the circuit forming element, the connection of the terminals can be effected easily, and besides a desired circuit can be easily obtained by the circuit structure of the circuit forming element.