Provided is a fibrous columnar structure aggregate having excellent mechanical properties, a high specific surface area, and excellent pressure-sensitive adhesive property. Provided is a fibrous columnar structure aggregate having excellent heat resistance, a high specific surface area, and excellent pressure-sensitive adhesive properties under temperature conditions ranging from room temperature to a high temperature. Provided is a fibrous columnar structure aggregate having a high specific surface area 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). Provided is a pressure-sensitive adhesive member using any such fibrous columnar structure aggregate. A fibrous columnar structure aggregate (1) of the present invention 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.