A liquid ejection head is provided with a recording element substrate having a plurality of ejection orifices for ejecting a liquid, the plurality of ejection orifices being arranged to form a row of the ejection orifices. In at least some of the plurality of the ejection orifices, each having one side and another side, the area of an inner wall of the ejection orifices is set to be larger on the other side than on the one side, the one side and the other side being defined by a plane which passes through the center of the ejection orifice, intersects with the row of the ejection orifices at right angles and extends along the direction of the depth of the ejection orifice.