A photomask includes a focus metrology mark region that includes a plurality of focus monitor patterns. To measure a focal variation of a feature pattern formed on a substrate, a substrate target for lithography metrology including a focus metrology mark formed on the same level as the feature pattern is used. A lithography metrology apparatus includes a projection device including a polarizer; a detection device detecting the powers of +/-n-order diffracted light beams from among output beams diffracted by the focus metrology mark of a to-be-measured substrate; and a determination device which determines, from a power deviation between the +/-n-order diffracted light beams, defocus experienced by the feature pattern.