A fibrous columnar structure aggregate having excellent mechanical properties, a high specific surface area, excellent heat resistance, excellent pressure-sensitive adhesive properties under temperature conditions ranging from room temperature to a high temperature, and such pressure-sensitive adhesive property that its adhesive strength for adherends different from each other in surface free energy does not change (the aggregate is free of adherend selectivity). The fibrous columnar structure aggregate (1) includes fibrous columnar structures having a plurality of diameters, in which the distribution width of the diameter distribution of the fibrous columnar structures having the plurality of diameters is 10 nm or more, and the relative frequency of the mode of the diameter distribution is 30% or less.