An ink jet head, includes: an actuator including a plurality of terminals; a wiring material including a base made of a flexible resin film on which a plurality of lands are arranged in arrays corresponding to the plurality of terminals, the wiring material of which one end is superimposed on a surface of the actuator, and which is extended in a direction parallel to the surface of the actuator; and a drive circuit for driving the actuator, wherein: the wiring material includes a small width portion, of which a width in a direction, perpendicular to an extended direction is smaller than that of the one end superimposed on the actuator, arranged on an extended portion; and the drive circuit is mounted on the extended portion; and wiring patterns are formed on the wiring material, for connecting the drive circuit and the plurality of lands.