A liquid jet head includes an actuator substrate having a principal surface on which ejection channels and non-ejection channels are formed, common electrodes formed on side surfaces of the ejection channels, individual electrodes formed on side surfaces of the non-ejection channels, individual electrode pads for connection to the individual electrodes, and common electrode pads for connection to the common electrodes. A groove is formed on the principal surface of the actuator substrate for isolating the individual electrode pads and the common electrode pads from one another. An external substrate has individual electrode terminals and common electrode terminals for connection to the individual electrode pads and common electrode pads, respectively. A connection wiring that connects the common electrode terminals to each other is formed along the groove to prevent an electrical short circuit between the connection wiring and the individual electrodes.