Abstract: A method for preparing an improved catalyst for use in the preparation of chlorine by the oxidization of hydrogen chloride with an oxygen-containing gas. The catalyst mainly comprises chromium oxide and can be used for a long period of time particularly under low oxygen content conditions, and the activity of the catalyst does not easily deteriorate, and in other words, the catalyst has a long life. Furthermore, there are disclosed the catalyst obtained by this preparation method, and a method for preparing chlorine from hydrogen chloride by the use of the catalyst. The method for preparing the improved catalyst comprises adding copper, an alkali metal and a rare earth metal, or adding chromium, copper, an alkali metal and a rare earth metal to a catalyst containing chromium oxide as a main component, and then calcining the catalyst at a temperature of 800.degree. C. or less.