According to one embodiment, an element substrate includes: heater arrays each having heaters arranged in parallel; corresponding transistors for driving the heaters included in the heater arrays; a first pad for supplying a voltage to be applied to the heaters; and a second pad for grounding the heaters. The element substrate is provided with a first wiring for connecting the first pad to the heaters, and a second wiring for connecting the heaters to the second pad. Furthermore, sizes of the transistors included in a heater array, of the heater arrays, provided at a position where intervals with respect to the first pad and the second pad are relatively large are set to be larger than the sizes of the transistors included in a heater array provided at a position where the intervals are relatively small.