A method of manufacturing an extreme ultraviolet mask including preparing a preliminary layout, forming a plurality of preliminary target patterns by using a plurality of preliminary spacer patterns formed by using the preliminary layout, evaluating presence or absence of an abnormal target pattern among the plurality of preliminary target patterns, preparing a layout configured to form a plurality of spacer patterns by modifying the preliminary layout when the plurality of preliminary target patterns include the abnormal target pattern, and manufacturing an extreme ultraviolet mask with the layout to form a plurality of target patterns by using the plurality of spacer patterns, wherein, the plurality of preliminary spacer patterns extend in one direction.