A lithography apparatus configured to form a pattern on a substrate through use of an original , the lithography apparatus comprising: a holding unit including a second mark and configured to hold the original on which a first mark is formed; a measuring unit configured to pick up an image of the first mark and an image of the second mark; and a control unit configured to: determine a reference position of a focus position of the measuring unit by adjusting the focus position of the measuring unit such that a contrast obtained from the image of the first mark of the original held by the holding unit a first time is equal to a contrast obtained from the image of the second mark of the holding unit; when the original is held by the holding unit a second time, cause the measuring unit to obtain the image of the first mark and the image of the second mark with the focus position of the measuring unit being adjusted to the reference position to obtain a first contrast of the image of the first mark and a reference contrast being a second contrast of the image of the second mark; and determine that the original is being abnormally held by the holding unit the second time when a change in the first contrast with respect to the reference contrast falls out of an allowable range. a holding unit including a second mark and configured to hold the original on which a first mark is formed; a measuring unit configured to pick up an image of the first mark and an image of the second mark; and a control unit configured to: determine a reference position of a focus position of the measuring unit by adjusting the focus position of the measuring unit such that a contrast obtained from the image of the first mark of the original held by the holding unit a first time is equal to a contrast obtained from the image of the second mark of the holding unit; when the original is held by the holding unit a second time, cause the measuring unit to obtain the image of the first mark and the image of the second mark with the focus position of the measuring unit being adjusted to the reference position to obtain a first contrast of the image of the first mark and a reference contrast being a second contrast of the image of the second mark; and determine that the original is being abnormally held by the holding unit the second time when a change in the first contrast with respect to the reference contrast falls out of an allowable range. determine a reference position of a focus position of the measuring unit by adjusting the focus position of the measuring unit such that a contrast obtained from the image of the first mark of the original held by the holding unit a first time is equal to a contrast obtained from the image of the second mark of the holding unit; when the original is held by the holding unit a second time, cause the measuring unit to obtain the image of the first mark and the image of the second mark with the focus position of the measuring unit being adjusted to the reference position to obtain a first contrast of the image of the first mark and a reference contrast being a second contrast of the image of the second mark; and determine that the original is being abnormally held by the holding unit the second time when a change in the first contrast with respect to the reference contrast falls out of an allowable range. <EOS>