The porous plate-shaped filler aggregate includes a plurality of the porous plate-shaped fillers. The porous plate-shaped fillers have a uniform plate shape with an aspect ratio of 3 or more, a minimum length of 0.1 to 50 μm, a porosity of 20 to 99%, and the deviation of the maximum length among a plurality of the porous plate-shaped fillers, which is obtained by the following formula, is 10% or less. Deviation of the maximum length (%)=standard deviation of the maximum length/average value of the maximum length×100 (Here, ‘maximum length’ is the longest length when the porous plate-shaped fillers are held between a pair of parallel planes.)