From 1973 December to 1986 September, we have experienced 2,500 cases of radiation treatment, of which 237 cases have been with bone metastasis. X-ray CT was examined on the 19 cases to detect the bone metastasis. The detective rate was 89.5% with bone scintigram alone improved to 94.7% with both bone scintigram and X-ray CT. Serum Alkali phosphatase (Al-p) were measured after and before radiation treatment on 147 cases. Values of Al-p increased on 64.6% cases measured and when values of Al-p were decreased after radiation treatment, good treatment effects were showed. Electron microscope disclosed that Al-p has existed around cell membrane of metastatic tumor cell. We considered there is a correlation between increment of Al-p in blood and contents of Al-p in bone metastatic tissues. Judgement of effects of radiation treatments were scored by three grades of pain relieving on 217 cases. Effective rate showed 87.5%. Effective rate increased by using high dose rates irradiation with small fraction. Effective cases in relieving pain had longer survival than less ones. 26 cases which could not walk due to spinal cord paresis were treated by irradiation only or irradiation with decompression surgery. Walk recovery rate was 33% by radiation treatment only, on the other hand, by treatment with decompression surgery, it was 20%. Regarding as side effect, radiation myelopathy hardly occurred about 50 Gy (conventional irradiation method). We think if longer survival time is hoped, about 50 Gy is needed.