Abstract: A substrate for a liquid ejecting head according to an exemplary embodiment of the present invention includes a first area having a plurality of ejection heaters and a driving circuit that is configured to supply electric energy to the plurality of ejection heaters disposed thereon, a second area having a signal supplying circuit that is configured to supply an electric signal to the driving circuit disposed thereon, and a heater that is configured to heat the substrate and that includes a first portion disposed in the first area and a second portion disposed in the second area. The magnitude of a current supplied to the first portion differs from the magnitude of a current supplied to the second portion.