A liquid jet head includes a piezoelectric body substrate having an upper surface, a lower surface, at least two groove arrays each having ejection grooves penetrating from the upper surface to the lower surface, and a first opening portion penetrating from the upper surface to the lower surface between the at least two groove arrays. Drive electrodes are provided on side surfaces of the ejection grooves and terminal electrodes are electrically connected to the drive electrodes. A flexible circuit board is electrically connected to the terminal electrodes and extends from the lower surface to the upper surface of the piezoelectric body substrate through the first opening portion.