A process for producing a liquid ejection head including a recording element substrate, an electrical wiring substrate provided with plural lead terminals, a support member provided with a concavity and a joining surface, and a sealant control wall arranged between a side surface of the recording element substrate and a side surface of the support member, the process including preparing a liquid ejection head in which the concavity and recording element substrate are mutually fixed, the joining surface and electrical wiring substrate are mutually fixed, and the lead terminals and connection terminal are mutually connected, and filling the sealant between the side surface of the recording element substrate and the side surface of the sealant control wall on the side of the recording element substrate followed by filling the sealant between a side surface of the sealant control wall on the side of the lead terminals and the lead terminals.