▎ 摘　　要

NOVELTY - Chemical sensor has a sensitive film (2), a first extracellular region peptide (4) of a transmembrane receptor immobilized on the sensitive film, a liquid phase arranged on the sensitive film, and a second extracellular region peptide of the transmembrane receptor contained within the liquid phase. USE - Chemical sensor for detecting a target substance in a specimen and for use in detecting apparatus (claimed). ADVANTAGE - The chemical sensor improves detection sensitivity, easily captures target substance, increases physical properties of the sensitive film, and performs detection with higher sensitivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a detecting apparatus, which comprises the chemical sensor, a detection unit that converts a change in physical properties of the sensitive film into a change in an electrical signal, a specimen introduction unit that takes the specimen into the liquid phase of the chemical sensor, and a processor that determines presence or absence or an amount of a target substance in the specimen by processing information of the electrical signal obtained from the detection unit; and (2) a detecting method for detecting a target substance in a specimen using a chemical sensor, which involves: (a) taking the specimen into the liquid phase of the chemical sensor; (b) detecting a change in physical properties of the sensitive film; and (c) determining presence or absence or an amount of the target substance in the specimen from a result of the detection. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of chemical sensor. 2Substrate 3Sensitive film 4First extracellular region peptide 7First electrode 8Second electrode