This paper introduces an oscillating heat pipe and describes the prospect of the technology for space applications. The concept of the oscillating heat pipe is entirely new one. It consists of a capillary channel, which turns many times between a heating section and a cooling section. Under operation, self-sustaining oscillatory flow of working fluid occurs. Due to the oscillatory flow, the liquid-vapor circulation cycle between the heating section and the cooling section is completed and heat is transferred as latent heat. The oscillating heat pipe has been developed and applied successfully in the field of terrestrial thermal control technology and it seems to be very promising also in space use.