Provided is a connector holder (25) suitable for use when connecting wire harnesses (10, 12) to each other by mating a plurality of connectors (40A to 40C, 41A to 41C). The connector holder is configured to be fitted into and fixed to a through hole (2a) in a vehicle body panel (2) that creates partitions, and to accommodate and hold the plurality of connectors (40A to 40C) that are connected to a group of electric wires of the wire harness (10) routed on one side of the vehicle body panel, the connectors being mated to connectors (41A to 41C) for a wire harness (12) routed on the other side of the vehicle body panel.