To provide a chemical sensor that can dissolve analytes in a gas in a liquid using a simple method, the chemical sensor comprising a sensor support section; a gas injection hole through which a gas containing an analyte is injected; a sample collection section in which the analyte contained in the gas injected through the gas injection hole is collected; a sample delivery section through which the analyte collected in the sample collection section is delivered; a sample reaction section including a reactant that causes a predetermined reaction with the analyte delivered through the sample delivery section; and a detection section in which the analyte reacted with the reactant in the sample reaction section is detected, wherein the sample collection section includes a Peltier element that liquefies water vapor contained in the gas injected through the gas injection hole.