The present invention provides an aligned carbon nanotube assembly constituted of carbon nanotubes each having a defective pore on its side surface, a method of manufacturing the aligned carbon nanotube assembly, a carbon-based electrode, and a power storage device. The aligned carbon nanotube assembly is formed by aggregating a large number of carbon nanotubes aligned in parallel along the same direction and having parallel orientation. In such a state that the aligned carbon nanotube assembly remains grown, the carbon nanotube constituting the aligned carbon nanotube assembly has a defective pore on its side surface. In a raman spectrum of the aligned carbon nanotube assembly in a Raman spectrometric method, when intensity of scattered light in D-band is represented by ID and intensity of scattered light in G-band is represented by IG, an ID/IG ratio is not less than 0.80.
