PROBLEM TO BE SOLVED: To obtain a new heat shock promoter comprising a stress-sensing gene derived from bacteria belonging to genus nitrosomonas, and capable of readily and speedily detecting a stress of ammonium oxidizing bacteria caused by various factors in the environment. SOLUTION: This heat shock promoter is the new one derived from bacteria belonging to genus nitrosomonas, and a stress of ammonium oxidizing bacteria caused by various factors in the environment can be readily and speedily detected by transforming ammonium oxidizing bacteria by introducing a fused gene obtained by bonding a structure gene coding a protein at the downstream of the promoter, culturing the recombinant body in a stress condition, and measuring the amount of expression of the structure gene. The heat shock promoter is obtained by forming a gene library by using a gene DNA derived from Nitrosomonas europaea IFO14298 strain, and screening the library by using a heat shock gene fragment of different creature as a probe.
