According to the general policy, namely, the pursuit of pure radiation
without any unreasonable heat load, the construction of various inser
tion devices has been scheduled at SPring-8. Most of them are of the i
n-vacuum type, which makes it possible to realize short-period devices
, so that the fundamental of undulator radiation may be obtained in th
e hard X-ray region. In addition, undulator radiation in the soft X-ra
y range down to 100 eV is available by introducing helical or figure-8
devices having low on-axis power density, which is very beneficial fo
r the optics, gratings or mirrors. A brief overview of the insertion d
evices at SPring-8 is presented with the initial commissioning results
.