A focus detection method for detecting a focus state based on object images formed through a photographing optical system in at least one focus detection area, while performing a search operation, includes determining at least one support area which overlaps the focus detection area; determining an in-focus position of the focusing lens group in the focus detection area to be an in-focus position of the focusing lens group when a brightness of the object is one of equal to and higher than a predetermined value; and determining an in-focus position of the focusing lens group upon an in-focus state being detected in the focus detection area and in the support areas which overlaps the focus detection area when the brightness of the object is lower than the predetermined value.