A random dispersion-type reflective polarizer, comprising: a core layer, which, to transmit first polarized light emitted from the outside and reflect second polarized light, includes a plurality of dispersed bodies in a base, the plurality of dispersed bodies having a different refractive index in at least one axis direction in the base, and 80% or more of the dispersed bodies in the base having an aspect ratio, indicating a ratio of the length of the minor axis to the length of the major axis, based on a cross-section in the plane perpendicular to the lengthwise direction, which is the direction in which the core layer has been elongated, of 1/2 or less, where the dispersed bodies having an aspect ratio of 1/2 or less are divided into three or more groups having different cross-sectional areas, the cross-sectional area of the first group is 0.2 μm 2 to 2.0 μm 2, the cross-sectional area of the second group is greater than 2.0 μm 2 and less than or equal to 5.0 μm 2 and the cross-sectional area of the third group is greater than 5.0 μm 2 and less than or equal to 10.0 μm 2, wherein among the dispersed bodies having an aspect ratio of 1/2 or less, the number of dispersed bodies of the first group is 30 to 50% and the number of dispersed bodies of the third group is 10 to 30%, wherein the number of the dispersed bodies of the first group divided by the number of the dispersed bodies of the third group is 3 to 5, and the first to third groups of dispersed bodies are aligned substantially parallel to the lengthwise direction and their arrangement within the plane perpendicular to said lengthwise direction is substantially random. a core layer, which, to transmit first polarized light emitted from the outside and reflect second polarized light, includes a plurality of dispersed bodies in a base, the plurality of dispersed bodies having a different refractive index in at least one axis direction in the base, and 80% or more of the dispersed bodies in the base having an aspect ratio, indicating a ratio of the length of the minor axis to the length of the major axis, based on a cross-section in the plane perpendicular to the lengthwise direction, which is the direction in which the core layer has been elongated, of 1/2 or less, where the dispersed bodies having an aspect ratio of 1/2 or less are divided into three or more groups having different cross-sectional areas, the cross-sectional area of the first group is 0.2 μm 2 to 2.0 μm 2, the cross-sectional area of the second group is greater than 2.0 μm 2 and less than or equal to 5.0 μm 2 and the cross-sectional area of the third group is greater than 5.0 μm 2 and less than or equal to 10.0 μm 2, wherein among the dispersed bodies having an aspect ratio of 1/2 or less, the number of dispersed bodies of the first group is 30 to 50% and the number of dispersed bodies of the third group is 10 to 30%, wherein the number of the dispersed bodies of the first group divided by the number of the dispersed bodies of the third group is 3 to 5, and the first to third groups of dispersed bodies are aligned substantially parallel to the lengthwise direction and their arrangement within the plane perpendicular to said lengthwise direction is substantially random.