A liquid ejection head includes: a casing, which is hollow, and has an opening at one end; a lid member, which is fixed to an end portion of the opening of the casing; and a member arranged inside the casing. The lid member has a liquid supply port. The member has a first liquid guide groove, and the casing has a second liquid guide groove. The second liquid guide groove extends from the end portion of the opening to a side opposite to the opening in the side wall inner surface of the casing, the first liquid guide groove extends to a side surface of the member which is in contact with or close to the side wall inner surface of the casing, and the first liquid guide groove and the second liquid guide groove are located so as to allow fluid communication therebetween.