Disclosed is an amine derivative represented by the following formula (1) or an acid addition salt thereof: ##STR1## wherein R.sup.1 represents a group ##STR2## a cyclopentyl group, cyclohexyl group, or a cycloheptyl group, R.sup.2 is a hydrogen atom or C1-C3 alkyl group which may be substituted by one or more hydroxyl groups, m is an integer falling in the range from 3 to 5 inclusive, and n is an integer falling in the range from 9 to 11 inclusive. Also, intermediates useful in the manufacture of the amine derivative (1), compositions for external application to the skin containing the amine derivative, and keratinization improvers containing the amine derivative as an active component are described. The compound (1) has excellent keratinization improving action, pigmentation preventing action, etc.