A method and a system for controlling temperature of a liquid in small flow amount, for supplying a liquid whose temperature is highly accurately controlled, as a flow of a small flow amount or an intermittent flow. A liquid supplied from a supply path is pressurized and introduced into a circulation path, and is temperature-controlled by a temperature control device in the circulation path, while being circulated in the circulation path by a pump in the pressurized condition. The liquid is supplied to an exterior device through a discharge path caused to branch from the circulation path, as a consecutive flow in a small amount or an intermittent flow in a small amount in a flow amount less than at least ½ times the flow amount in the circulation path, by adjusting a discharge valve provided in the discharge path.