PROBLEM TO BE SOLVED: To obtain histamine dehydrogenase suitably usable for determination of histamine carried out in a wide field such as food industry, marine industry, food sanitation, medical treatment, analyzer industry. SOLUTION: A bacterial strain belonging to the genus Rhizobium, having characteristics of specifically acting on histamine and the following physical and chemical propertied of formation of 1 mol of 4-imidazolylacetaldehyde and 1 mol of ammonia by oxidative deamination reaction of 1 mol of histamine in the presence of an electron receptor, a substrate specificity of specifically acting on histamine, 65-75 deg.C optimal temperature, deactivation condition by temperature (stable at 0-60 deg.C by treatment at pH 8.0 for 15 minutes) and molecular weight (about 150,000 (subunit about 71,000×2) is cultured in a medium and the histamine dehydrogenase is collected from the culture product. In the culture, histamine or a histamine salt is added to the medium and a large amount of the enzyme is produced and accumulated in the culture product.