The disclosed process for rejuvenation treatment of a photoresist development waste mainly containing a photoresist and tetraalkylammonium (TAA) ions comprises at least a simple membrane separation step of treating the photoresist development waste or a treated solution derived from the photoresist development waste with a nanofiltration membrane (NF membrane) to obtain a concentrate (NF concentrate) mainly containing impurities such as the photoresist and a higher-purity permeate (NF permeate) mainly containing TAA ions. The NF concentrate and/or the NF permeate, preferably the NF permeate, is desirably subjected to a step of concentration and refining by electrodialysis or electrolysis and/or a step of refining by ion exchange treatment, for example, with an anion exchange resin and/or a cation exchange resin in one of the H form and the TAA form. The NF permeate may advantageously be passed through the concentrating cells of an electrodialysis unit while passing the NF concentrate through the desalting cells of the electrodialysis unit to further recover TAA ions remaining in the NF concentrate, whereby the amount of wastewater discharged as the desalted waste can be decreased. The NF membrane separation step is preferably effected in multiple stages.