Biosensor

A biosensor comprising a development layer where an inspection target solution is developed, said biosensor holding at least, a marker reagent part where a marker reagent is held so as to be dissolved by the development of the inspection target solution in a part of the development layer, and a reagent immobilization part where a reagent which specifically reacts to an analysis target in the inspection target solution is immobilized in a part of the development layer, which part is chromatographically downstream relative to the marker reagent part, wherein

• the development layer is provided with areas where a cellular component contraction agent and a bleaching reagent having bleaching action for fading colored components in a liquid sample are supported respectively so as to be dissolved, at least in parts of downstream of a sample application area where the inspection target solution is applied, in the direction of the inspection target solution permeating.