Disclosed herein are a pack case constructed in a structure in which a plurality of battery cells are mounted in the pack case to electrically connect the battery cells with each other, wherein the pack case includes an upper case and a lower case constructed in a hollow structure in which the upper case and the lower case are coupled with each other while the battery cells are mounted between the upper case and the lower case, each case is integrally provided at the inner part thereof with a plurality of spacers for supporting the battery cells, and each case is provided at the outer part thereof with a plurality of ventilation openings which communicate with the interior of each case, and a battery pack including the pack case. The pack case according to the present invention has effects in that a plurality of battery cells are stably mounted in the pack case in a compact structure through a simple assembly process, heat generated from the battery cells is effectively removed during the charge and discharge of the battery cells, and an additional safety unit, such as a detection member and/or a protection circuit module, is easily mounted to the pack case.