Intravenous immunoglobulin (IVIG) is a potential second line of therapy for pemphigus, with increasing evidence of its effectiveness and safety, although oral corticosteroids remain the first treatment for pemphigus. IVIG is usually applied in severe cases of pemphigus, particularly pemphigus vulgaris (PV). Pemphigus foliaceus (PF) caused by immunoglobulin PF autoantibodies to desmoglein 1 (Dsg1) is usually milder than PV. However, PF cases are occasionally resistant to corticosteroids and require long-term treatment to control the disease, leading to various adverse effects. IVIG was used in patients with relatively mild PF, who were resistant to therapies with corticosteroids and dapsone. We assessed the disease severity by Pemphigus Disease Area Index (PDAI) and measured anti-Dsg1 antibody indices by enzyme-linked immunosorbent assay, before and 4 months after IVIG. Four Japanese female PF patients (57.3 ± 8.6 years) were treated with a single cycle of IVIG (400 mg/kg per day for five consecutive days) in combination with the previous therapies. Within 1–2 months of addition of IVIG, all PF cases showed remarkable improvement of skin lesions, and PDAI also markedly decreased. For 2 years after IVIG, no apparent exacerbation was observed. Anti-Dsg1 antibody indices decreased in all cases during the 2 years. IVIG could be a potential treatment for not only severe cases of PV but also mild and refractory cases of PF. IVIG may trigger the shift from intractable condition to remission via non-pathogenic anti-Dsg1 antibodies or some mechanisms excluding anti-Dsg1 antibody.