This invention relates to a head substrate capable of reducing power loss and achieving a high integration degree or downsizing at low cost. The head substrate includes at least plural printing elements, plural driving elements which drive the plural printing elements, and plural level converters which boost the voltage of a driving signal for driving the plural driving elements, to a voltage enough to drive the respective driving elements. The head substrate further includes plural converted voltage generation circuits, arranged close to each other on the head substrate, for applying a common voltage for the boosting operation of level converters belonging to each group prepared by grouping the plural level converters. The plural converted voltage generation circuits share a reference voltage generation portion formed from a resistor and for generating a reference voltage for determining voltage values generated by the plural converted voltage generation circuits.