We develop standards and measurement techniques for X-ray, γ-ray, and β-ray ionizing radiation, which are used mainly in radiation protection. For medical applications, we have been developing the air kerma standards for mammography X-rays, the absorbed dose to water standards for Co-60 γ-rays, and the air kerma standards for brachytherapy sources. We have installed a new clinical linac for radiotherapy and are currently developing the absorbed dose to water standard for high-energy photon beams. In addition, we are developing a technique for measuring the X-ray free electron laser intensity and the absorbed dose for ion beams.