Gas alarm device and gas detection method

alarm device according to claim 1, wherein

• the first condition is a heating extension starting condition,
• the second condition is a heating repeating condition,
• the first determination section determines whether or not the electrical characteristics of the sensing section satisfy the heating extension starting condition,
• the second determination section determines whether or not the electrical characteristics of the sensing section satisfy the heating repeating condition,
• the heating control section extends a heating period of time of the heater section if the first determination section determines that the electrical characteristics satisfy the heating extension starting condition, and repeats extension of the heating period of time and makes the second determination section repeat a determination as long as the second determination section determines that the electrical characteristics upon lapse of extension of the heating period of time satisfy the heating repeating condition, and
• the gas detection section determines that the detection target gas is detected if the second determination section determines that the electrical characteristics upon lapse of extension of the heating period of time satisfy the heating repeating condition.

The gas alarm device according to claim 3, wherein

• the heating extension starting condition and the heating repeating condition are an identical condition,
• the electrical characteristics of the sensing section is an electrical resistance value of the sensing section,
• the heating control section:
• extends a heating period of time of the heater section if the first determination section determines that the electrical resistance value is equal to or less than a threshold value;
• and
• repeats, with a predetermined number of times or a predetermined drive time as an upper limit, extension of the heating period of time and makes the second determination section repeat a determination as long as the second determination section determines that the electrical resistance value upon lapse of extension of the heating period of time is equal to or less than the threshold value, and
• the gas detection section determines that the detection target gas is detected if the second determination section determines that the electrical resistance value upon lapse of extension of the heating period of time is equal to or less than the threshold value even after the extension of the heating period of time has been repeatedly performed for the upper-limit number of times or the upper-limit drive time.