To provide an ink jet head and an ink jet printer capable of forming a clear image on a recording sheet while suppressing nonuniformity of density and exhibiting high productivity.

In an ink jet head comprising a head substrate having an upper surface arranged with a large number of heating resistors at a density of N (a natural number of 120 or more) dpi, and a panel arranged to form a specified gap with respect to the head substrate, resistance of each heating resistor is set within a range of ±3.0% for the average resistance A of all heating resistors. The large number of heating resistors are sectioned into a plurality of blocks where one unit includes D heating resistors calculated by a formula D=[N/60]. Average resistance of heating resistors existing in each block is set such that the difference from the average resistance of heating resistors existing in an adjacent block falls within a range of 0.2% for the average resistance A of all heating resistors.