A liquid ejection head including: a support member, a plurality of printing element boards arranged linearly on the support member, an electric wiring member fixed to the support member, and configured to transmit an electrical signal necessary to eject a liquid to the plurality of printing element boards, a plurality of conductive members arranged in an arranging direction of the plurality of printing element boards, and configured to electrically connect the plurality of printing element boards to the electric wiring member, and a thermosetting sealing member extending in the arranging direction and covering the conductive members, connecting points of the printing element boards with the conductive members, and connecting points of the electric wiring member with the conductive members, wherein the sealing member is divided at, at least one place in the arranging direction.