Glucocorticoids (GC) are effective for treating IgG4-related disease (IgG4-RD); however, relapse is often observed. We conducted a retrospective multicentre study to investigate risk factors in GC regimens associated with relapses of IgG4-RD. Data on 166 patients with definitive IgG4-RD diagnosis were collected from 12 institutions. Comprehensive surveillance of clinical backgrounds and GC regimens as well as multivariate analysis of factors associated with treatment responses and relapses was performed. To determine the initial maximal GC dose, the patients were stratified into three groups depending on the initial prednisolone (PSL) dosage: <0.39, 0.4-0.69 and >0.7 mg/kg/day. The multivariate analysis extracted the disease duration and reduction speed of initial GC dose. Patients treated with initial GC <0.39 or >0.7 mg/kg/day of PSL showed higher relapse rates than those treated with 0.4-0.69 mg/kg/day. The relapse rates were significantly higher in patients with fast reduction of the initial dose (>0.4 mg/day) than in patients with slow reduction (<0.4 mg/day). To avoid relapse, 0.4-0.69 mg/kg/day of initial PSL with slow reduction speed (<0.4 mg/day) is needed in the early treatment of IgG4-RD.