A liquid ejection head includes a recording element substrate provided with elements formed on one surface of the substrate for generating energy for ejecting liquid as well as first and second supply ports each piercing between both surfaces of the substrate for supplying the liquid to the elements; and a support member provided with first and second liquid storage portions, first and second communication paths that respectively allow the first and the second supply ports to communicate with the first and second liquid storage portions, the support member supporting the other surface of the substrate. The length of the first communication path is longer than that of the second communication path. The horizontal cross-sectional area of the first communication path in a direction perpendicular to the liquid supply direction is larger than that of the second communication path.