AbstractThe oblique injection system of high power millimeter waves is designed and installed for plasma profile control and electron cyclotron current drive in the Heliotron E helical device. The previous 106.4 GHz electron cyclotron heating (ECH) perpendicular injection system has been modified by installing a movable mirror and a grating polarizer, which are required for toroidally oblique injection. Although the beam size at the resonant position is larger due to diffraction when scanning the beam direction, it is still smaller than the plasma radius so that we can experimentally investigate the dependence of plasma profiles on the toroidal injection angle. Low power and high power test results on the movable mirror and the polarizer have shown that the system works well as designed. The system has successfully been applied to the plasma experiment on Heliotron E. Plasma experimental results using this system are also shown.