A gas purification device and an ion mobility spectrometer. The gas purification device comprises: a first purifying agent container (4), a second purifying agent container (5) and a valve (3) communicating the first purifying agent container (4) and the second purifying agent container (5). The valve (3) is configured to allow, in a first state of said valve, gas to flow from the second purifying agent container (5) to the first purifying agent container (4), and allow, in a second state of said valve, gas to flow from the first purifying agent container (4) to the second purifying agent container (5).