It is intended to provide a preventive agent or a therapeutic agent for a disease caused by abnormal bone metabolism, particularly for osteoporosis, which is more effective than ever before. By combined application of N-hydroxy-4-{5-[4-(5-isopropyl-2-methyl-1,3-thiazol-4-yl)-phenoxy]pentoxy}-benzamidine or a salt thereof and one or more compounds selected from the group consisting of etidronic acid, clodronic acid, pamidronic acid, tiludronic acid, risedronic acid, minodronic acid, ibandronic acid, zoledronic acid, and salts thereof, a higher bone resorption inhibitory action compared with the administration of a single compound is exhibited, and an excellent preventive effect and therapeutic effect for a disease caused by abnormal bone metabolism, particularly for osteoporosis can be obtained.