Liquid ejection head substrate

A liquid ejection head substrate, in which a plurality of units are arranged, each of the plurality of units including:

• a pressure generating element formed on a first surface of a support substrate;
• and
• a pair of independent liquid chambers, which are formed on both sides of the pressure generating element so as to be opposed to each other, and are opened to the first surface of the support substrate,
• the liquid ejection head substrate comprising, in the support substrate:
• a first common liquid chamber communicating to a plurality of independent liquid chambers on one side of the pair of independent liquid chambers;
• a second common liquid chamber communicating to a plurality of independent liquid chambers on another side of the pair of independent liquid chambers;
• and
• a partition wall separating the first common liquid chamber and the second common liquid chamber from each other,
• wherein the partition wall extends in an arrangement direction of the pressure generating elements,
• wherein the partition wall has a width smaller than a distance between the pair of independent liquid chambers,
• wherein the partition wall has a shape inflected regularly in the arrangement direction in plan view of the support substrate in a thickness direction of the support substrate, and
• wherein the pair of independent liquid chambers of each of the plurality of units are arranged so that a straight line connecting opening centers of the pair of independent liquid chambers is prevented from being orthogonal to a center-of-gravity line of the partition wall in an extending direction of the partition wall.