Cables W are spliced to one another by insulation displacement terminals 22 in sub connectors 21A and 21B, when a cable holder 11 that contains ends of a plurality of cables is fitted into containing sections of the sub connector housings 21A and 21B. A tab 22c of each insulation displacement terminal 22 is connected to each joint bus bar 24 disposed in a joint connector housing 31. The sub connectors 21A and 21B are interconnected when the sub connectors 21A and 21B are fitted into containing sections of the joint connector housing 31.