An LN storage tank is disclosed. The LNG storage tank includes: a lower insulation board for insulating LNG from the outside; a heating member placed on the lower insulation board; a main secondary barrier attached on the heating member; an upper insulation board attached on part of the main secondary barrier; and an auxiliary secondary barrier attached on the other part of the main secondary barrier, wherein a first adhesive layer may be interposed between the main secondary barrier and the auxiliary secondary barrier.