A liquid feeding method for feeding liquid in a minute flow path is provided. The minute flow path includes flow paths 43a, 43c, 43d connected to each other directly at respective first ends. The liquid feeding direction of blood S in the minute flow path is controlled by creating a high-pressure state at a second end of the flow path 43a located across the blood S, while creating a low-pressure state or a closed state at a second end of the flow paths 43d, 43c.