An image processing device configured to detect a salient region from an original image, comprising: a superpixel image generating unit configured to generate a multi-scale superpixel image made of superpixels, each superpixel being made of pixels adjacent to one another and whose luminance values and/or chromaticity are similar, from the original image; a prior probability calculating unit configured to calculate a prior probability of the salient region for each of the pixels of the original image; a region generating unit configured to generate a convex hull having high possibility of containing a salient region by connecting, with a straight line, corner points extracted from the original image; a likelihood calculating unit configured to calculate a likelihood of the salient region, for each of the pixels of the original image so that the likelihood of the salient region for the corresponding pixel is the higher, the larger the number of pixels included in the convex hull having the same luminance value and/or chromaticity as that of said corresponding pixel is; and a salient region detecting unit configured to calculate a posterior probability of the salient region by using the prior probability and likelihood of the salient region, wherein the prior probability calculating unit calculates the prior probability of each pixel of the original image with summations of parameters summed over the superpixel image scales and increases the prior probability with an increasingly large color distance from adjacent superpixels included in the same scale, and wherein an edge point correcting unit is configured to perform a correction at each superpixel image scale, in a case where the number of edge points included in one of the superpixels is equal to or less than a predetermined number, so as to decrease the prior probability of each of pixels constructing said superpixel, and in the case where the number of edge points included in said superpixel is larger than the predetermined number, so as to set the prior probability of each of the pixels constructing said superpixel to zero. a superpixel image generating unit configured to generate a multi-scale superpixel image made of superpixels, each superpixel being made of pixels adjacent to one another and whose luminance values and/or chromaticity are similar, from the original image; a prior probability calculating unit configured to calculate a prior probability of the salient region for each of the pixels of the original image; a region generating unit configured to generate a convex hull having high possibility of containing a salient region by connecting, with a straight line, corner points extracted from the original image; a likelihood calculating unit configured to calculate a likelihood of the salient region, for each of the pixels of the original image so that the likelihood of the salient region for the corresponding pixel is the higher, the larger the number of pixels included in the convex hull having the same luminance value and/or chromaticity as that of said corresponding pixel is; and a salient region detecting unit configured to calculate a posterior probability of the salient region by using the prior probability and likelihood of the salient region, wherein the prior probability calculating unit calculates the prior probability of each pixel of the original image with summations of parameters summed over the superpixel image scales and increases the prior probability with an increasingly large color distance from adjacent superpixels included in the same scale, and wherein an edge point correcting unit is configured to perform a correction at each superpixel image scale, in a case where the number of edge points included in one of the superpixels is equal to or less than a predetermined number, so as to decrease the prior probability of each of pixels constructing said superpixel, and in the case where the number of edge points included in said superpixel is larger than the predetermined number, so as to set the prior probability of each of the pixels constructing said superpixel to zero.