An iron-based sintered body with a rustproof function comprises a layer containing 0.01 to 5 at % of indium on the surface of the iron-based sintered body, or an iron-based sintered body with a rustproof function contains 0.01 to 5 at % of indium throughout the sintered body, and the iron-based sintered body having iron as its principal component is manufactured by performing sintering in a gas atmosphere containing indium vapor or indium. Thereby obtained is an iron-based sintered body, as well as the manufacturing method thereof, capable of easily improving the rustproof effect without having to hardly change the conventional process.