A biopsy case of basal cell adenoma of the parotid gland was reported. The tumor was spherical in shape, measured 1.1cm×0.9cm and encapsulated by a fibrous tissue. The cut surface showed a uniform yellow appearance. Histologic picture of the tumor was acinic or tubular monomorphic adenoma with secretion of PAS-positive substance. Electron microscopically tumor cell revealed 3 kinds of cells, that is, secreting cell, non-secreting cell and myoepithelial cell. The acinus was composed of one-layered secreting cells and myoepithelial cells situated at the acinic base. The tubulus was consisted of admixture of secreting cells and non-secreting cells. Myoepithelial cells were seen at the base of the tubulus. Interstitial tissue was small in amount and collagen fibers, basement membrane-like substance and myoepithelial cells were seen in it.