A liquid jet head has an actuator substrate, a cover plate and a nozzle plate. The actuator substrate includes a groove array formed by alternately arraying an ejection groove and a dummy groove, and a common chamber communicating with one end of the ejection groove but not communicating with the dummy groove. The cover plate is provided on a top surface of the actuator substrate so as to cover the groove array, and includes one chamber communicating with the common chamber and another chamber communicating with another end of the ejection groove. The nozzle plate is provided on a bottom surface of the actuator substrate so as to cover the groove array, and includes a nozzle communicating with the ejection groove.