A device for detecting a solid-liquid distribution in a solid-liquid separation column of a solid-liquid separation device, comprising: a light irradiation means for irradiating an inside of the solid-liquid separation column of a freeze concentration device with visible light; a CCD camera as a photographing means for picking up an image of the inside of the solid-liquid separation column irradiated with the visible light by the light irradiation means; and being characterised in that it further comprises: a movement means for moving the photographing means in an up-and-down direction of the solid-liquid separation column; an image analysis means for analyzing a data piece of an image picked up by the photographing means, wherein the analysis of an image data piece made by the image analysis means is a process of dividing the image data piece into image data pieces of any small regions and averaging numerical values indicating lightness and darkness of pixel data pieces of the divided small regions; and a determination means for determining a solid-liquid distribution state in the solid-liquid separation column based on a result of an analysis made by the image analysis means, wherein the determination means determines that solid-liquid distribution states are different from each other when a difference between average values of the numerical values indicating the lightness and darkness of the pixel data pieces of the small regions exceeds a predetermined threshold, the average values being obtained in different areas in an up-and-down direction of the solid-liquid separation column. a light irradiation means for irradiating an inside of the solid-liquid separation column of a freeze concentration device with visible light; a CCD camera as a photographing means for picking up an image of the inside of the solid-liquid separation column irradiated with the visible light by the light irradiation means; and being characterised in that it further comprises: a movement means for moving the photographing means in an up-and-down direction of the solid-liquid separation column; an image analysis means for analyzing a data piece of an image picked up by the photographing means, wherein the analysis of an image data piece made by the image analysis means is a process of dividing the image data piece into image data pieces of any small regions and averaging numerical values indicating lightness and darkness of pixel data pieces of the divided small regions; and a determination means for determining a solid-liquid distribution state in the solid-liquid separation column based on a result of an analysis made by the image analysis means, wherein the determination means determines that solid-liquid distribution states are different from each other when a difference between average values of the numerical values indicating the lightness and darkness of the pixel data pieces of the small regions exceeds a predetermined threshold, the average values being obtained in different areas in an up-and-down direction of the solid-liquid separation column. a movement means for moving the photographing means in an up-and-down direction of the solid-liquid separation column; an image analysis means for analyzing a data piece of an image picked up by the photographing means, wherein the analysis of an image data piece made by the image analysis means is a process of dividing the image data piece into image data pieces of any small regions and averaging numerical values indicating lightness and darkness of pixel data pieces of the divided small regions; and a determination means for determining a solid-liquid distribution state in the solid-liquid separation column based on a result of an analysis made by the image analysis means, wherein the determination means determines that solid-liquid distribution states are different from each other when a difference between average values of the numerical values indicating the lightness and darkness of the pixel data pieces of the small regions exceeds a predetermined threshold, the average values being obtained in different areas in an up-and-down direction of the solid-liquid separation column.