The utility model relates to a cooling box is examined to marking machine heat, including the cooling box body that holding marking machine heat was examined, the inner chamber of cooling box body carries out the refrigerated cooling chamber as examining marking machine heat, is provided with cooling air source interface and exhaust hole and through wires hole on the cooling box body, and cooling box body below is provided with the support, and the through wires hole includes optic fibre through wires hole and cable through wires hole. The utility model discloses can effectively reduce marking machine heat and examine the ambient temperature of body, it is normal to guarantee that the signal action is examined to heat, and the marking machine realizes a casting blank sign function can for the continuous casting billet marking, and the emergence of having stopped muddy steel problem had both alleviateed and has also laid the solid foundation for the normal application of quality judgment system because marking machine trouble arouses the work load of the artifical manual number of retouching.