In the present invention, a detection device has a chip holder, an excitation-light radiation unit, and a heat source. The chip holder is used for positioning a detection chip that has: a prism; a metal film; a trapping body; and a substrate. The excitation-light radiation unit radiates excitation light at the reaction site via the light-entry surface of the detection chip, which is held by the chip holder. The heat source is disposed in a position so as to face, in a non-contacting manner, the surface of the prism of the detection chip held by the chip holder that is closest to the reaction site, and so as not to interfere with the optical path of the excitation light. The chip holder positions the detection chip while in contact with only the reverse surface of the substrate and/or a convex portion positioned on the prism.