Fecha de publicación: 17/05/2007 Fuente: WIPO "miel" Galactosylceramide analogues represented by the following formula (1) or (2). (wherein X and Y each represent S or O, R1 and R2 each represent an alkyl group or an alkenyl group each having 9 to 35 carbon atoms. R3 represents an alkyl group or an alkenyl group each having 2 to 30 carbon atoms.) It is provided a β-glucocerebrosidase activator which is easily available, and external skin preparations and a method of activating β-glucocerebrosidase, in which improvement in formation of horny layer transmission barrier is expected by activating β-glucocerebrosidase so that an improved effect in rough skin is also expected.