A method of sterilizing a separation membrane module reduces damage of a ceramic separation membrane, a sterilization process device achieves the method of sterilizing, and an apparatus produces chemicals. The method of sterilizing the separation membrane module includes a ceramic-containing separation membrane including a temperature raise step of raising the temperature of the separation membrane module to a predetermined sterilization temperature by feeding sterilization water having a controlled temperature and pressure so that a rate of temperature change of the separation membrane module is 6.0° C. or less per minute, and a sterilization step of sterilizing the separation membrane module at a predetermined temperature for a predetermined time.