A liquid ejection head includes a substrate including, at a surface thereof, an ejection energy generating means for generating ejection energy for ejecting liquid, a flow path forming member provided with an ejection outlet, the substrate further including a liquid supply opening, penetrating therethrough, for supplying the liquid to be ejected by the ejection energy to a flow path of the flow path forming member; a reinforcing member connected to a back side of the substrate; a first penetrating electrode, penetrating the substrate from a front side to the back side thereof, for supplying electric power to the ejection energy generating means; and a second penetrating electrode penetrating the reinforcing member from a front side to a back side thereof, the second penetrating electrode being electrically connected to the first penetrating electrode.