Target substance detection method, target substance detection kit, and target substance detection system

A method for detecting a target substance in a sample using an immuno chromatographic method, comprising:

• trapping the target substance and a reporter substance on a support in a binding state represented as “support—aptamer probe—target substance—aptamer probe—reporter substance” using an aptamer probe,
• wherein the aptamer probe has an aptamer portion capable of binding to the target substance, and a binding partner portion capable of binding to both a binding portion immobilized on the support and a binding portion immobilized on the reporter substance;
• and
• detecting a signal from the reporter substance.

A detection system for detecting a target substance in which an immuno chromatographic method is used, comprising:

• an immuno chromatographic test piece having a detection region on which a binding portion is immobilized;
• a reporter substance on which a binding portion is immobilized;
• and
• an aptamer probe having a binding partner portion that binds to both the binding portion of the detection region and the binding portion of the reporter substance, and an aptamer portion that binds to the target substance.