Full measuring range infrared gas detector

The utility model provides a full measuring range infrared gas detector, which comprises a metal casing provided with an optical filter and a base provided with a detector. The metal casing is packed together with the base. The full measuring range infrared gas detector is characterized in that N+1 optical filters with different wave lengths are arranged on the metal casing. The detector comprises one reference thermal pile chip and N identical measuring thermal pile chips, a first optical filter and the reference thermal pile chip form a reference passage, the remaining N optical filters are respectively in one-to-one corresponding with the N measuring thermal pile chips, and the remaining N optical filters and the N measuring thermal pile chips form N paths of measuring passages. The N is a natural number larger than 3. The gas detector has the advantages of being convenient to use, practical and high in precision.