The invention provides a dimension measuring apparatus, a dimension measuring method, and a program for dimension measuring apparatus. The dimension measuring apparatus is configured by: a movable stage; a measurement setting data storing section that holds feature amount information and measured position information; a low-magnification imaging section that photographs a workpiece with a low magnification; a workpiece detecting section that specifies a position and a posture of the workpiece in the low-magnification image based on the feature amount information; a stage controlling section that controls the movable stage 12 based on the specified location and posture such that the position to be measured of the workpiece stays within the high-magnification field of view; a high-magnification imaging section that photographs with a high magnification the position to be measured; an edge extracting section that extracts an edge of the position to be measured from the high-magnification image; and a dimension value calculating section that obtains a dimension value of the position to be measured.