Bullous pemphigoid (BP) is a autoimmune bullous skin disorder that is caused from autoantibody that attack dermoepidermal junction. Not only skin biopsy, immunoblotting (IB) that can detect the serum antibodies to BP180 and BP230 can be used to diagnose BP. As BP can occur at elderly patients and it can be fatal by its severity, early diagnosis and treatment is needed. We report a case of BP that had typical clinical presentations with unusual IB finding. A 79-year-old man presented for multiple erythematous patches with bulla formation on whole body for 6 months. By subepidermal blister at H&E staining and linear IgG at direct immunofluorescence microscopy analysis, he was diagnosed to BP. But although autoantibody to BP230 was detected, autoantibody to BP180 was not detected at IB and autoantibody to 170 was found instead. Although the response of the treatment including systemic methylpredenisone, cyclosporine and topical steroids was slower than other BP patients, there was no more new lesion 4 months after the treatment. We report this case by finding the phenomenon that there can be a variation in the result of IB analysis of clinically BP patient.