An installation structure of an external filter case for a refrigerator is provided. The filter case may include a main body that provides an inner space in which an internal line may be installed and water filters may be installed, and a cover that covers the inner space of the main body and is detachably coupled with the main body. The main body may have an open front side and may include bosses that protrude from its bottom face. The cover may include insertion holes into which the bosses may be inserted. A lower portion of the main body may be coupled with a lower portion of the cover. Magnets may be installed in upper portions of the main body and the cover, respectively, such that the main body and the cover may be coupled with each other by a magnetic force.