Generally, an infant with impaired hearing meets many difficulties in the process of growing up. A patient with bilateral atresia of the ear (first and second branchial arch syndrome) was followed over a long period of time. The patiant was fitted with a hearing aid in the right ear initially. External canalplasty was subsequently performed, and we were able to fit her with binaural hearing aids. After the operation, based on the consults of a questionaire, she reported to enjoy having a conversation with her friends. Binaural hearing was a decided improvement on the previous situation. Sound lateralization ability was measured by a self recording apparatus (Rion Co., TD-01). This test demonstrated that both the air (fitting of the binaural hearing aids) and bone sound lateralization abilities were close to those in normal subjects.