The present invention relates to a method for adjusting temperature by increasing gas molecular density. The method includes: filling a chamber with at least one gas to a predetermined pressure, wherein the predetermined pressure is higher than 1 atm and lower than or equal to 50 atm flowing the gas in the chamber to a temperature adjusting device, wherein the temperature adjusting device includes a cooler and a gas returning device cooling the gas by the cooler and returning the gas to the chamber by the gas returning device.
