To evaluate the efficacy and safety of R484iv by intravenous intermittent administration to patients with primary osteoporosis in comparison with sodium risedronate hydrate (RIS) by oral administration every day. To evaluate also the dose response of R484iv.

Inclusion Criteria:

• Patients with fragile bone fracture
• Patients in whom either of study site analysis value of bone density of lumbar spine, proximal part of femur or neck of femur is less than 80% of young adult mean (YAM).
• Patients with 1 - 5 bone fractures in 4th thoracic spine (Th4) - 4th lumbar spine (L4)
• Ambulatory

Exclusion Criteria:

• Patients with disease lowering bone volume secondarily (secondary osteoporosis)
• Patients receiving at least one time of of oral bisphosphonate preparations within 6 months before the start of administration of the study drug
• Patient with disorder delaying the passage of food through esophagus