ECRH antenna system for central cell of GAMMA 10 was newly installed. This system was designed to improve the calculated Poynting flux reaching the resonance surface and the beam path. The power transmission efficiency has been improved from about 60 to 70 % and the beam passes the center of the resonance surface. Performance test of this system was carried out with low power and we got the performance that we expected. This system was installed to GAMMA 10 and the initial electron heating result with it has been obtained.