Recent development of superconducting accelerator dipole magnets in Japan is described. A series of NbTi/Cu dipoles in the region of 5 to 10 T is being developed at KEK. The maximum field will depend on the maximum proton energy of the TRISTAN ring from 300 to 600 GeV. On the other hand, development of a special Nb
3Sn/Cu dipole magnet in the region of 10 T has been started for the future multi-TeV pp and

colliding beam accelerator.