A sample observation device for observing a sample held in a sample container using fluorescent light, the sample observation device comprising: an irradiation unit that irradiates the sample with planar light along a first direction being a Z-axis; a scanning unit that scans the sample along a second direction being an Y-axis orthogonal to the first direction with respect to an irradiation surface of the planar light, wherein a direction orthogonal to the Y-axis within the plane orthogonal to the Z-axis is an X-axis; an image formation unit that forms images of fluorescent light and scattered light generated in the sample due to the irradiation with the planar light; an imaging unit that captures at least a part of a light image of the fluorescent light formed by the image formation unit and outputs first image data, and captures at least a part of a light image of the scattered light formed by the image formation unit and outputs second image data; an image processing unit that generates a fluorescent light image on the basis of a plurality of pieces of first image data obtained for the second direction and generates a scattered light image on the basis of a plurality of pieces of second image data obtained for the second direction; and an analysis unit that specifies an area in which there is the sample in the fluorescent light image on the basis of the scattered light image, sets an analysis area in the fluorescent light image on the basis of the area in which there is the sample, and analyzes an intensity of the fluorescent light in the analysis area, wherein the image formation unit has an observation axis which is inclined with respect to an irradiation surface for the planar light, at an inclination angle (θ) formed by the first direction and the observation axis; the first image data corresponds to an XZ image on the irradiation surface of the fluorescent light, and the second image data corresponds to an XZ image on the irradiation surface of the scattered light; the image processing unit compresses the plurality of pieces of first image data and the plurality of pieces of second image data in the first direction, wherein the first image data compressed in the first direction indicates a luminance of the fluorescent light in the X-axis direction, and the second image data compressed in the first direction indicates a luminance of the scattered light in the X-axis direction, and synthesizes the compressed plurality of pieces of first image data and the compressed plurality of pieces of second image data in the second direction to obtain the fluorescent light image and the scattered light image, and the analysis unit extracts areas in which there is a sample by extracting a contour shape in the scattered light image. an irradiation unit that irradiates the sample with planar light along a first direction being a Z-axis; a scanning unit that scans the sample along a second direction being an Y-axis orthogonal to the first direction with respect to an irradiation surface of the planar light, wherein a direction orthogonal to the Y-axis within the plane orthogonal to the Z-axis is an X-axis; an image formation unit that forms images of fluorescent light and scattered light generated in the sample due to the irradiation with the planar light; an imaging unit that captures at least a part of a light image of the fluorescent light formed by the image formation unit and outputs first image data, and captures at least a part of a light image of the scattered light formed by the image formation unit and outputs second image data; an image processing unit that generates a fluorescent light image on the basis of a plurality of pieces of first image data obtained for the second direction and generates a scattered light image on the basis of a plurality of pieces of second image data obtained for the second direction; and an analysis unit that specifies an area in which there is the sample in the fluorescent light image on the basis of the scattered light image, sets an analysis area in the fluorescent light image on the basis of the area in which there is the sample, and analyzes an intensity of the fluorescent light in the analysis area, wherein the image formation unit has an observation axis which is inclined with respect to an irradiation surface for the planar light, at an inclination angle (θ) formed by the first direction and the observation axis; the first image data corresponds to an XZ image on the irradiation surface of the fluorescent light, and the second image data corresponds to an XZ image on the irradiation surface of the scattered light; the image processing unit compresses the plurality of pieces of first image data and the plurality of pieces of second image data in the first direction, wherein the first image data compressed in the first direction indicates a luminance of the fluorescent light in the X-axis direction, and the second image data compressed in the first direction indicates a luminance of the scattered light in the X-axis direction, and synthesizes the compressed plurality of pieces of first image data and the compressed plurality of pieces of second image data in the second direction to obtain the fluorescent light image and the scattered light image, and the analysis unit extracts areas in which there is a sample by extracting a contour shape in the scattered light image.