The purpose of the present invention is to provide a detection method which can safely recover a remaining sample from a detection device without causing a biological disaster. In order to achieve at least one of these goals, this detection method involves: a sample collection step for collecting a sample from the sample holding well, and transferring the same to a detection chip; a detection step for detecting the detected substance captured in the detection chip by means of a detection unit; and, after the sample collection step, a remaining sample recovery step for collecting the sample remaining in the sample holding well and transferring this to a sample recovery well. At that time, after the remaining sample recovery step, the surface area of the opening in the sample recovery well is smaller than the surface area of the opening in the sample holding well.