Electrospinning is a versatile technique widely used to produce polymer fibres with diameters ranging from several micrometres to tens of nanometres. This unique technique enables the production of thin fibres and charges the fibres in parallel. However, precise comparisons between electrospinning and other charging techniques have been limited. In this study, the charging properties of electrospun microfibre mats fabricated using atactic poly(styrene) (aPS) were compared with those of corona-charged microfibre mats fabricated using the same material (aPS) and possessing the same structure. The results showed that the surface potentials of electrospun aPS fibre mats were approximately three times higher than those of corona-charged fibre mats, demonstrating that a significantly large amount of charge could be stored in electrospun fibre mats. A large amount of stored charge was maintained even after 240 d of storage in low-humidity, atmospheric, and high-humidity environments. Furthermore, mathematical models explaining the effective surface charge densities of electrospun and corona-charged fibre mats were proposed using the recently proposed model of stored charge distribution in fibre mats. Therefore, the clarified unique charging properties of electrospun aPS microfibre mats originally charged via electrospinning pave the way for the development of appropriate applications of electrospun charged polymer microfibres, submicrofibres, and nanofibres.