Provided is a liquid ejection head, including: an ejection unit including: a recording element substrate including a plurality of recording elements configured to generate energy; and a support member formed of a plate-like member and configured to support the recording element substrate, the support member including: a liquid chamber configured to store liquid therein, and an inlet formed in the liquid chamber so as to allow the liquid to flow into the liquid chamber; a flow path unit including a liquid path through which the liquid is supplied into the ejection unit from a liquid tank storing the liquid therein; a joint member sandwiched between the support member and the flow path unit and configured to seal the liquid; and a buffer chamber formed in a space defined by the joint member, the ejection unit, and the flow path unit and configured to retain gas therein.