The microwave power transmission technology, a key technology for space solar power system (SSPS) which is being spotlighted as a technology capable of solving global environmental problem as well as the energy problem, is drawing attention as a technology applicable on the ground (for power transmission to solitary islands, remote areas, etc.). Mitsubishi Heavy Industries, Ltd. (MHI) has, therefore, undertaken a joint project with the Radio Science Center for Space and Atmosphere of Kyoto University, a leading institute in the world in the field of microwave power, and developed the microwave power transmission experimental equipment in view of applying the technology to space solar power satellite and ground receiving equipment. This paper describes the features of the technology and its future prospect.