A Si--SiC based fired body includes a plurality of silicon carbide (SiC) particles serving as an aggregate, and silicon (Si) which serves as a binder and which is filled into gaps between the above-described silicon carbide particles, wherein the maximum particle diameter of the above-described silicon carbide particles is 0.5 mm or more, the content of silicon is 5 to 40 percent by mass, and the porosity is 0 to 5%. Preferably, the Si--SiC based fired body is in a thick-walled shape having a thickness of 20 to 200 mm.