An ink jet head is provided which includes: nozzles forming a predetermined array; liquid chambers respectively provided for the nozzles; pressure generation elements respectively provided for the liquid chambers which respectively discharge liquid in the liquid chambers; individual supply flow paths which respectively supply the liquid to the liquid chambers; a common supply flow path that is connected to each individual supply flow path and supplies the liquid into each individual supply flow path; and a liquid supply unit that circulates the liquid of the common supply flow path so as to make the liquid flow in one direction in the common supply flow path. The common supply flow path has a shape in which a cross-sectional area is increased and decreased at a predetermined interval. Each individual supply flow path is provided at a position where the cross-sectional area of the common supply flow path is increased.