Provided is a quality management system for a radiation therapy apparatus. The quality management system includes: an input/output unit displaying selectable quality management items； a quality management order error determining unit determining whether there is an error in the order of the quality management items that are selected and arranged by the input/output unit； and a quality management execution control unit performing control such that quality management is executed in the order of the quality management items that are determined by the quality management order error determining unit to have no error in the arrangement order thereof.
