A liquid ejection head includes a plurality of liquid chambers each including an energy generating element that generates energy for ejecting a liquid, an ejection opening that ejects the liquid, and a liquid supply opening that supplies the liquid, the liquid flowing in a first direction in the plurality of liquid chambers, and the plurality of liquid chambers being arranged in a second direction that intersects the first direction, and a plurality of first side walls that extend in the first direction and that form walls on both sides of the plurality of liquid chambers. In the liquid ejection head, each of the plurality of first side walls includes a fragmenting portion that fragments each of the plurality of first side walls in the first direction.