PURPOSE: To improve the indicated-temperature detecting accuracy of a molding for detecting heat history so as to strictly manage a baking process and, at the same time, to manage baking in a high-temperature region in an inert gas atmosphere by using an unbaked ceramic molding containing Si3N4 and/or SiC and a sintering assistant in a specific composition as the molding.

CONSTITUTION: The fluctuation of the burning shrinkage factor of the title molding is reduced and the indicated-temperature detecting accuracy is improved to ±5°C by setting the mixing ratio of Si3N4 in the molding at ≥60mol%. In addition, the molding is made to detect heat history within a temperature of 1,500-2,000°C by setting the mixing ratio of a sintering assistant at ≤40mol%. In addition, when the mixing ratio of the sintering assistant of boron, carbon, etc., is set at ≤30mol%, the molding can be used in a vacuum or inert gas atmosphere. Then an unbaked molding is formed of a raw material having such a composition by forming chord sections 12 and 22 in complete roundness sections 11 and 11 by pressing and chamfering 14 corner sections, and then, printing a mark 13 indicating the surface side while the particle size, green density, etc., of the raw material are strictly managed. When the molding is formed in such a shape, no warping occurs and the dimensions of the molding can be accurately measured.