CHEMICAL SUBSTANCE DETECTION DEVICE AND CLEANING DEVICE

PROBLEM TO BE SOLVED: To provide a chemical substance detection device which can refresh a sensor surface before measurement regardless of a kind of a sensor and structure and in which the refreshing is less likely to affect the detection of the chemical substance, and to provide a cleaning device used in combination with the chemical substance detection device.SOLUTION: The chemical substance detection device includes: a chemical substance detection element 1; a cell 2 which houses the chemical substance detection element and can reduce pressure inside; a gas supply flow path 12 for supplying a gaseous sample to the cell; a valve 13 for blocking movement of the gas between a gas suction port 11 and the cell 2; a gas discharge flow path 21 for discharging the gaseous sample from the cell; a vacuum pump 23 for reducing the pressure inside the cell and the gas flow path; and gas suction means 24 for supplying the gaseous sample to the cell.