Optical gas sensor device

An optical gas sensor device comprising:

• a light source that emits infrared radiation to a detection target gas;
• an optical filter that transmits infrared radiation having passed through the detection target gas, the optical filter being a band-pass filter, a center wavelength of transmittance at vertical incidence (θ=0°) of the optical filter being shifted by a predetermined shift amount to a longer wavelength side from a wavelength corresponding to maximum absorption in an absorption spectrum of the detection target gas;
• a light receiver that detects infrared radiation entering the light receiver via the optical filter and generates a detection signal;
• and
• an optical cover that covers the light source, the optical filter, and the light receiver,
• wherein the optical cover includes a pipe-shaped light guide part that guides infrared radiation entering from the light source to the light receiver via the optical filter by reflecting the infrared radiation on an inner surface and that has a circular or oval cross section perpendicular to an axial direction.