A 54-year-old woman diagnosed with eosinophilic granulomatosis accompanied by polyangiitis (EGPA) was in remission with prednisolone (PSL) and mepolizumab treatment. During the disease course, vasculitis recurrence was not apparent, but her asthma became uncontrollable and was accompanied by elevated antineutrophil cytoplasmic antibody (ANCA) levels. Asthma control did not improve after switching from mepolizumab to another biological agent, benralizumab. Consequently, the treatment with benralizumab was changed to tezepelumab, after which her symptoms immediately improved and her ANCA levels decreased, enabling reduction in the PSL dosage. This case highlights the potential of tezepelumab to reduce ANCA levels in EGPA-related severe asthma.