In order to provide a method for collecting a droplet attached on an external surface of a needle into a capillary tube, the present invention is a method for collecting a droplet attached on an external surface of a needle into a capillary tube, the method comprising steps of: (a) preparing a substrate comprising a capillary tube; a flexible thin film; a liquid-repellent film; and a hole; (b) moving the needle in the Z-direction to move the droplet from the external surface of the needle to the surface of the liquid-repellent film; (c) allowing the droplet to arrive at an inlet of the capillary tube by moving the needle more in the Z-direction, so as to suck the droplet into the capillary tube by a capillary phenomenon.