A case of pemphigus vulgaris in a six-year-old Japanese girl is presented. She first developed vesicles and ulcerations in oral and laryngeal mucous membranes, showing a hoarse voice and fits of coughing with excessive slavering. She had skin blisters six months later. Biopsy of the skin lesion demonstrated the intraepidermal blister in a suprabasal location. Direct immunofluorescence (IF) of the skin lesion revealed deposits of IgG and C3. Indirect IF showed serum anti-ICS antibody titer at 1:640. She was diagnosed as having pemphigus vulgaris. Treatment with oral prednisolone (1 mg/kg) proved effective. This is the first case of infantile pemphigus vulgaris in Japan.