A head substrate is capable of integrating driver transistors while keeping the size small even at high nozzle density, while integrating a functional circuit such as a temperature sensor or energy adjustment circuit. An ink supply port, a heater array which is arrayed along the longitudinal direction of the ink supply port and includes a plurality of heaters, a transistor array which is arrayed along the arrayed direction of the heater array and includes a plurality of transistors for driving a plurality of heaters, and a logic circuit which drives the transistor array are arranged on the head substrate. The logic circuit is arranged between the heater array and the transistor array.