The present invention relates to an apparatus for treating waste containing mercury and a method for recovering high purity elemental mercury using the apparatus. More specifically, the present invention may provide a method that can more economically and stably recover high purity elemental mercury from waste containing mercury using an apparatus for recovering mercury from waste containing mercury, the apparatus comprising: a thermal desorption unit; a dust control unit; and a condensation and recovery unit, which are connected in series. The present invention has an advantage in that, compared to a conventional simple heat treatment-condensation method, a high recovery rate of mercury is achieved and high purity mercury can be obtained.