An image processing device (10) comprises the following: an image acquisition unit (1) for acquiring an image in which markers for calibration are captured; an edge detection unit (2) for detecting the edges of the markers in the image; a polygon generating unit (3) for estimating a plurality of straight lines on the basis of the edges and generating a virtual polygon region that is surrounded by the plurality of straight lines, the generation being carried out in the image in a region thereof including regions other than those where markers are installed; and a camera parameter calculation unit (4) for calculating camera parameters on the basis of the characteristic amount, with respect to the image, of the virtual polygon region and the characteristic amount, with respect to real space, of the virtual polygon region.