TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: When the pH of alumina hydrogel fluctuates alternately between alumina hydrogel melting pH region and Boehmite gel precipitation pH region, alumina hydrogel formation substance is added, crystal of alumina hydrogel is grown and gamma-alumina support is prepared by pH swing process. The pH of catalyst metallic compound solution is 1.8-3. The noble metal dispersion degree after forming catalyst is 60% or more. The noble metal is preferably platinum and its amount is 0.3-2 wt.%. The alkali metal is potassium and its amount is 0.001-1 wt.%. The baked catalyst metal support is impregnated into alkali metal compound solution and dried at a temperature ranging from room temperature to 200degreesC for 0.5-48 hours. The final hydrogen reduction process is performed using hydrogen airflow at a temperature of 350-550degreesC for 0.5-48 hours. The dehydrogenation catalyst is regenerated with hydrogen gas at 250-550degreesC with gas hourly space velocity of 10-100/hour. The dehydrogenation conversion ratio of hydrogenated aromatic compound in a reaction condition of liquid hourly space velocity (LHVS) of 2/hour, temperature of 30degreesC and under normal pressure, is 90% or more.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: When the pH of alumina hydrogel fluctuates alternately between alumina hydrogel melting pH region and Boehmite gel precipitation pH region, alumina hydrogel formation substance is added, crystal of alumina hydrogel is grown and gamma-alumina support is prepared by pH swing process. The pH of catalyst metallic compound solution is 1.8-3. The noble metal dispersion degree after forming catalyst is 60% or more. The noble metal is preferably platinum and its amount is 0.3-2 wt.%. The alkali metal is potassium and its amount is 0.001-1 wt.%. The baked catalyst metal support is impregnated into alkali metal compound solution and dried at a temperature ranging from room temperature to 200degreesC for 0.5-48 hours. The final hydrogen reduction process is performed using hydrogen airflow at a temperature of 350-550degreesC for 0.5-48 hours. The dehydrogenation catalyst is regenerated with hydrogen gas at 250-550degreesC with gas hourly space velocity of 10-100/hour. The dehydrogenation conversion ratio of hydrogenated aromatic compound in a reaction condition of liquid hourly space velocity (LHVS) of 2/hour, temperature of 30degreesC and under normal pressure, is 90% or more. EXAMPLE - Suspension of aluminum hydroxide slurry was obtained by mixing sodium aluminate aqueous solution and dilute sulfuric acid. The solution was stirred and aluminum hydroxide was precipitated. The addition operation of sodium aluminate aqueous solution and dilute sulfuric was performed repeatedly. The obtained precipitate was filtered, washed, molded, dried and baked at 500degreesC for 3 hours. The obtained gamma-alumina support had pore volume of 0.713 cm3/g, pore diameter of 119 Angstrom and surface area of 240 m2. About 90 volume% of the support had pore diameter of 90-300 Angstrom . 0.4 wt.% chloroplatinic acid aqueous solution (79 g) having pH of 2 was impregnated into porous gamma-alumina support (20 g) for 3 hours. The support was dried at 120degreesC for 3 hours and baked under air at 400degreesC for 3 hours. The baked substance was cooled and impregnated into 0.52 wt.% potassium nitrate aqueous solution (10 g). The substance was removed and dried at 120degreesC for 3 hours and reduced at 400degreesC under hydrogen circulation for 15 hours to form dehydrogenation catalyst. The catalyst contained platinum (0.6 wt.%) and potassium 0.1 wt.%. The dehydrogenation catalyst was used for dehydrogenation of methyl cyclohexane. The conversion ratio of methane cyclohexane was 95.2%. Toluene selectivity and yield were 99.9% and 94.1%, respectively.