GAS DETECTION DEVICE, GAS DETECTION METHOD, AND GAS DETECTION PROGRAM

A gas detection device that gives a notification of a detected gas on the basis of a captured image obtained by capturing an image of a monitoring target, the gas detection device including: a gas detection unit that detects gas on the basis of the captured image and gives a notification of the detected gas; an input unit that receives input information from a user; a mask candidate region extraction unit that extracts a mask candidate region that is a candidate region of a mask region for which a notification of gas detection is suppressed; and a mask generation unit that generates mask data indicating the mask region, in which the gas detection unit gives a notification of a gas detected outside the mask region, and the mask generation unit generates, as the mask data, a region in which first mask candidate region information input from the input unit matches second mask candidate region information extracted by the mask candidate region extraction unit.