To achieve thermonuclear fusion it is inevitable to develop high power microwave and millimeter wave sources for plasma heating. In 1990, working group was organized as a collaboration study in National Institute for Fusion Science to review the present status of development on high microwave source. We report the review of development on high power klystron and gyrotron, FEL and microwave power source by REB. Development of high power klystron is almost finished except for cooling of the window, cavity and collector. As for the gyrotron oscillating with the whispering gallery mode one must overcome the same problem for CW operation. In the quasi-optical gyrotron, these is no special progress for increasing the frequency and efficiency. Though the experimental evidence on autoresonance in the development of peniotron is performed, output power and frequency is much smaller than that of the gyrotron. It is difficult to increase in the pluse width of FEL having giant of GW level with several ten ns and the utilization for plasma heating is limited. In addition, we summarize microwave and millimeter wave oscillators with high power which are running in the laboratories and the institutes. (author).