Provided is a radioactive bone diagnostic agent that gives a high radioactivity accumulation ratio between bone and blood from the early stage after drug administration and enables imaging in a short time after administration. The following chemical formula (II) (wherein X represents-(CH2) mCO-, Y represents-(CH2) n-, R represents H, OH or a halogen atom, m and n are independent of each other; m represents an integer of 1 to 3, and n represents an integer of 0 to 4) or a salt thereof薬剤投与後早期から高い骨と血液との放射能集積比を与え、投与後短時間での撮像が可能となる放射性骨診断剤を提供する。下記の化学式(II)(式中Xは-(CH2)mCO-を示し、Yは-(CH2)n-を示し、RはH、OH又はハロゲン原子を示し、m、nは互いに独立し、mは1~3の整数、nは0~4の整数を示す)で表されるビスホスホン酸誘導体又はその塩