In this experimental report, We introduce an idea of thermal corrosion in sandwich panel. In brief, Because the structures of sandwich panel are easily collapsed by thermal damage caused by a fire, it is very difficult to investigate a point and origin of fire. Therefore, If the shapes of thermal corrosion are reconstructed according to change of temperature and lapse time by experiment in sandwich panel, it is very simple task that fire scene investigators search for a point and origin of fire. As a result, we present the difference of thermal corrosion between samples which are applied heat by many-sided variable, such as temperature, heating time, lapse time, humidity, and others.