A gas measurement device wherein: a light projection unit is provided at one end side of a hollow fiber into which gas to be measured is introduced; light from a light source is irradiated into the hollow fiber; a detector is disposed past the other end side of the hollow fiber, which is sealed by a transparent member; light passing through the hollow fiber is detected; a measurement and control unit measures the gas to be measured on the basis of the detected light; an optical filter unit is provided in a space between the other end of the hollow fiber and the detector and transmits light that has passed through the hollow fiber and is within the light absorption band of the gas; and the hollow fiber has a bent shape such that the detector is placed in a position outside of the area extending linearly from the light source of the light projection unit to the hollow fiber.
