Pressure sensors are widely used in industries, including cars and coolers. Highly accurate pressure sensors are capable of corresponding to changes in the surrounding temperature. Additionally, the manufacturing process of pressure sensors greatly impacts the cost and degree of precision. This study undertook to examine the manufacturing process of pressure sensors, especially those using ceramic diaphragm. Ruthenium oxide (RuO2) was used instead of strain gauge for piezoresistance. TC thermistor (temperature coefficient) resistance compensated for changes in outdoor air temperature. Furthermore, thick-film resistors were precisely adjusted with laser trimming technology. These processes resulted in the production of a high accuracy diaphragm pressure sensor having an ability to correspond to changes in outdoor temperatures.