A plurality of signal conductor wires connected respectively to signal lead patterns, and a plurality of power conductor wires connected respectively to power lead patterns are formed on a connector tail and are arranged to extend in a leading-out direction. A pitch of the power conductor wires is twice larger than a pitch of the signal conductor wires. A sufficient insulating gap is secured between the adjacent power conductor wires, and therefore there is no fear that the short-circuiting occur even when a high drive voltage is applied.