A liquid ejection head substrate according to an exemplary embodiment of the present invention includes a plurality of ejection heaters arranged in a first region, a drive circuit that is arranged in the first region and configured to supply electric energy to the plurality of ejection heaters, a signal supply circuit that is arranged in a second region and configured to supply an electric signal to the drive circuit, and a substrate heating heater including a first portion arranged in the first region and a second portion arranged in the second region, in which a resistance value per unit length along a direction of a current of the first portion is different from a resistance value per unit length along a direction of a current of the second portion.