Abstract: An object dimension measuring apparatus consists of: a CCD camera mounted on an X- and a Y-axis table with its optical axis aligned with a Z-axis; a specimen table containing a light source and having its specimen mounting surface formed transparent; a light diffusion plate mounted on the specimen; and a computer. Using the CAD data, the computer moves the CCD camera. From the measured values obtained from the photographed images of the end portions of the specimen and from the distance traveled by the CCD camera, the computer calculates the dimensions of the specimen.