A method for producing a sintered body is provided. The method for producing the sintered body comprising: forming a green body by molding a composition for forming a green body into a specified shape to obtain the green body, the composition comprising powder constituted of a metallic material and a binder containing a first resin which is decomposable by ozone; first debinding the green body by exposing the green body to a high ozone content atmosphere to decompose the first resin and remove the decomposed first resin form the green body to obtain a brown body; exposing the thus obtained brown body at least once to a low ozone content atmosphere whose ozone concentration is lower than an ozone concentration of the high ozone content atmosphere to obtain an intermediate brown body; and sintering the intermediate brown body which has been exposed to the low ozone content atmosphere to obtain the sintered body. By using the composition mentioned above, it is possible to safely, easily and cost-effectively produce a metal sintered body having a reduced metal oxide amount and improved properties (dimensional accuracy). Such a sintered body is also provided.