This invention relates to a pharmaceutical composition containing 4-[(4-thiazolyl)phenoxyl]alkoxy-benzamidine derivatives expressed by the following formula 1 for the prevention and treatment of osteoporosis and more particularly, to the use of 4-{5-[4-(5-isopropyl-2-methyl-1,3-thiazol-4-yl)phenoxyl]pentoxy}-benzamidine or N-hydroxy-4-{5-[4-(5-iso-propyl-2-methyl-1,3-thiazol-4-yl)phenoxyl]pentoxy}-benzamidine expressed by the following formula 1, which is known as an antagonist of leukotriene-B4 receptor, as a pharmaceutical composition for the prevention and treatment of osteoporosis. [Formula 1], wherein, R is a hydrogen atom or a hydroxy group.