1. An information processing apparatus comprising: an image processing unit for smoothing a tissue sample image obtained by staining and then imaging a biological tissue containing parenchymal cells and stromal cells so that luminance values of cell components of each of the parenchymal cells become less than those of each of the stromal cells; a mask generation unit for generating, through generating a binary image by binarizing the tissue sample image smoothed by the image processing unit, a mask for removing a region of the stromal cells from the tissue sample image; a superimposing unit for superimposing the mask generated by the mask generation unit on the tissue sample image; and a counting unit for counting the number of the parenchymal cells with each staining intensity contained in the tissue sample image with the mask superimposed thereon, wherein a diagnosis based on the tissue sample image is supported.