TO INCREASE A TISSUE REGENERATION ABILITY OF A LIVING BODY SUCH AS A COLLAGENS PRODUCTION ABILITY OF FIBROBLAST IN THE DERMIS IN A SKIN DEFECT AREA TYPIFIED BY A LARGE WRINKLE OR WOUND, A FLAVANONE DERIVATIVE SUCH AS FARREROL IS USED AS AN ACTIVE INGREDIENT OF AN EXTERNAL PREPARATION FOR SKIN. FURTHER, TO EFFICIENTLY SCREEN A SUBSTANCE HAVING AN EXCELLENT EFFECT ON PROMOTING WOUND HEALING, THE REMODELLING ACTION OF COLLAGEN FIBER BUNDLE IS TESTED BY USING SKIN WOUND MODEL.