An image processing apparatus comprising: an input unit to input a fluorescent image and a morphological image of a tissue, wherein a specific biological substance expressed at a first structure of a cell in the tissue is stained by a fluorescent substance, the fluorescent image illustrates at least one fluorescent bright point which represents expression of the biological substance in the tissue, and the morphological image illustrates a morphology of a second structure of a cell in the tissue and comprises the same range of the tissue as the fluorescent image; a feature amount extraction unit to extract a feature amount of the second structure from the morphological image; a bright point extraction unit to extract the fluorescent bright point from the fluorescent image; a region of interest determination unit to determine a region of interest on the basis of the feature amount of the second structure and the distribution of the fluorescent bright point; a cell morphology extraction unit to extract the second structure of the cell from the morphological image; a discrimination unit to discriminate a fluorescent bright point corresponding to the second structure on the basis of the feature amount of the second structure and a positional relation of the fluorescent bright point, wherein the region of interest determination unit determines the region of interest of a cell assigned to the second structure on the basis of the distribution of the fluorescent bright point corresponding to the second structure; a calculation unit to calculate a number of the fluorescent bright points respectively corresponding to the second structure, wherein when the number of the fluorescent bright points is more than a predetermined value, the region of interest determination unit determines a closed curve or a polygon as the region of interest, wherein the closed curve or the polygon surrounds the fluorescent bright point respectively corresponding the second structure, and when the number of the fluorescent bright points is equal to or less than the predetermined value, the region of interest determination unit determines, as the region of interest, a dilation region which is prepared by dilation processing of the second structure and which comprises therein a predetermined ratio of the fluorescent bright point corresponding to the second structure. an input unit to input a fluorescent image and a morphological image of a tissue, wherein a specific biological substance expressed at a first structure of a cell in the tissue is stained by a fluorescent substance, the fluorescent image illustrates at least one fluorescent bright point which represents expression of the biological substance in the tissue, and the morphological image illustrates a morphology of a second structure of a cell in the tissue and comprises the same range of the tissue as the fluorescent image; a feature amount extraction unit to extract a feature amount of the second structure from the morphological image; a bright point extraction unit to extract the fluorescent bright point from the fluorescent image; a region of interest determination unit to determine a region of interest on the basis of the feature amount of the second structure and the distribution of the fluorescent bright point; a cell morphology extraction unit to extract the second structure of the cell from the morphological image; a discrimination unit to discriminate a fluorescent bright point corresponding to the second structure on the basis of the feature amount of the second structure and a positional relation of the fluorescent bright point, wherein the region of interest determination unit determines the region of interest of a cell assigned to the second structure on the basis of the distribution of the fluorescent bright point corresponding to the second structure; a calculation unit to calculate a number of the fluorescent bright points respectively corresponding to the second structure, wherein when the number of the fluorescent bright points is more than a predetermined value, the region of interest determination unit determines a closed curve or a polygon as the region of interest, wherein the closed curve or the polygon surrounds the fluorescent bright point respectively corresponding the second structure, and when the number of the fluorescent bright points is equal to or less than the predetermined value, the region of interest determination unit determines, as the region of interest, a dilation region which is prepared by dilation processing of the second structure and which comprises therein a predetermined ratio of the fluorescent bright point corresponding to the second structure.