Abstract
The development of the auditory hair in the human fetal cochlea is observed under scanning electron microscope. It is well known that the cytological maturation of the cochlea begins at the basal turn and then proceeds to the apical turn. The auditory hair development follows the those regional difference of cytological maturation. The mature type of the auditory hair is seen in the basal turn, but only early stage of hair development is seen in the apical turn of the same cochlea. Sometimes the atypical auditory hair cell with one pair of stepwise arranged hair on one cell surface, is seen. Since atypical hair cell cannot observe in postfetal cochlea, it seems that these cells disappear during fetal life. The extra internal hair cell which is located in modiolus side of the internal hair cell row, is frequently seen in fetal cochlea.
