Thin-film heaters made of molybdenum silicide (MoSi2) were fabricated by RF magnetron sputtering, and the heating characteristics of these heaters in a high vacuum were evaluated. The crystal structure of thin-film was hexagonal contrary to the tetragonal one of the target. MoSi2 thin-film heaters deposited outside an alumina crucible showed almost linear resistance-temperature (R-T ) characteristics. However, resistance decreased due to repeated heatings. The heaters generated almost no contamination in vacuum. The temperature of the crucible reached 1000°C at an electric power of 190 W.