This continuous sterilization device sterilizes a member constituting a flow path by causing a sterilization medium for sterilizing the member to flow through the member, causes a sterile liquid subjected to sterilization treatment to flow through a pipe, while performing a series of treatments including heat treatment, holding treatment, and cooling treatment on the sterile liquid, controls the flow rate, temperature, and pressure thereof to preset conditions, and switches a liquid to flow through the flow path from the sterile liquid to a liquid to be sterilized.