Abstract: A retainer (A) aligns and retains ends (E) of branch wires (W1) and wires (W2) to be connected with the branch wires (W1) through the use of a wire retaining portion (U). The wire retaining portion (U) is formed with cavities (42) which have a specified depth and into which the wires (W1, W2) are individually inserted, and contact members (60) for coming into contact with the wires (W1, W2) inserted into the cavities (42). The contact members (60) prevent the wires (W1, W2) from coming out of the cavities (42). The contact members (60) also move away from the wires (W1, W2) when necessary. The ends (E) of the branch wires (W1) and the wires (W2) to be connected with the branch wires (W1) can be aligned and retained during a wire arranging operation. After forming a bundle of wires, the wires (W1, W2) can be released from the retainer (A) with their ends (E) aligned. The aligned ends (E) can be easily processed at one time. The number of the wires (W1, W2) to be retained can be easily confirmed.