Autoclave is a closed heating device used for the sterilize a surgical instrument using steam at a temperature of 121 ° C and pressure, 1.1 bar for approximately 15 minutes. The designed tool uses an ATMega 328 microcontroller used as the main controller, driver heater to turn on the heater so that the heating process occurs. The temperature and pressure sensors read 121 ° C temperature with a pressure of 1.1 bar. It will be displayed on the LCD. This autoclave tool is equipped with a steam exhaust system automaticall which can carry out steam removal if the selenoid valve driver gets voltage from the microcontroller. Testing on this tool will be compared with tools for temperature gauges namely thermometers, timer measurements compared to stopwatches and sterilization tests using an autoclave tape. At temperature measurements obtained a correction value of 0.14 while the measurement of 900 seconds timer obtained a correction value of 3.3 whereas for the sterilization experiment, the effective sterilization time is 15 to 20 minutes. From the measurement and sterilization test, it can be concluded that the measurement has a correction value that is not far away and this autoclave modification tool can doing the sterilization process with 15 minutes pof an effective time.