1. An image measuring apparatus, comprising: an image capture unit which captures an image of a measurement subject; an import unit which imports the image of the measurement subject which is captured by the image capture unit; a binarization unit which binarizes the image which is imported by the import unit; a contour detection unit which recognizes graphic information in the image which is binarized by the binarization unit and detects a contour of the graphic information; a corner detection unit which detects corners of the graphic information based on the contour which is detected by the contour detection unit; a setting unit which respectively sets edge detection tools on lines of the contour including the corners detected by the corner detection unit; and a measurement unit which measures the graphic information by the edge detection tools which are set by the setting unit, wherein the setting unit sets the edge detection tools so that a longitudinal center axis of the detection tool respectively substantially overlaps a center portion of a line between adjacent corners detected by the corner detection unit, a length of the center portion corresponding to a length of the respective edge detection tool.